There seems to be quite a bit of misinformation on the topic of BRP’s BUDS Diagnostic system. The following is an attempt to clarify how the BRP BUDS system and licence keys access Really works!!!

System Overview 
The BUDS system utilizes BRP windows based software, a USB CAN interface called the MPI-2 (Multi Protocol Interface) , the approporate BUDS software depending on the BRP type you are working on and a licence key code.
In the most basic terms, you can’t do anything with the BUDS software unless you have the MPI-2 plugged into your computer , have the correct software installed and have the appropriate licence key code for your specific MPI-2.
The key code is a 20 digit alpha numeric string that is generated by a key code generator. BRP dealers are provided a key code by BRP via the BOSSWEB download site , licence keys for our systems are provided buy email after the customer provides confirmation their install is correct and they are ready for keys .
The key code is only valid for a specific MPI. It will not work on a different MPI!!!, Additionally, the key code has an expiration date built into the code & the key code will not work beyond the expiration date. BRP typically sets this time to one year. For our kits we can provide licence keys in 1 , 2 , 5 or 10 year lifespans depending on customer requirements.
With the release of BUDS version 3 and subsequent 'letter' designation BUDS programs BRP has added a new wrinkle to their BUDS software security. Now the key code generated for BUDS must be entered into the BUDS software within 24 hours of the key code being generated. If you do not enter the key code within the 24 hour period, it becomes invalid.
If you do buy a BUDS system from an ebay sale or closing down dealer please understand that it will NOT WORK without first installing the updated software AND unlocking the system with licence keys that we can provide NO PROBLEM for ANY
MPI-2 unit , either our units or genuine BRP units.
The BUDS software is available to work with the following BRP product lines:
SeaDoo PWC , Seadoo SportBoat , SkiDoo, CanAm ATV, CanAm SSV and Spyders.
However, the key code is generated in such a way that only that portion of the software that the dealer is authorized for by BRP is unlocked. As an example, a BRP dealer that sells CanAms and SeaDoos will receive BUDS access for Can-Ams and SeaDoos, but will not have access to the other product lines. In Some cases the software for the other product lines are present in the BUDS program, the key code simply prevents the dealer from accessing them or even seeing that they exist.
for a comprehensive guide to BUDS hardware & software applications please
see the link here : BUDS Chart
The BUDS hardware for SeaDoo, Sportboats and SkiDoo consists of several components: the MPI, DESS Post Interface, DESS Post Adapter, and several interconnect cables.  The MPI-2 is the the only component of the BUDS system that connects to a computer via a USB port. The DESS or DESS 4 tec post interface is utilized for programming DESS keys.
On the newer models with I-Control, BRP has eliminated the need for the DESS post interface for key programming. I-Control equipped skis use the DESS post on the Ski to program keys , For these PWC models and all other models such as CanAm ATV, CanAm SSV and Spyders just the MPI-2 unit & connection cable is needed for all diagnostic & key programming functions.
Since the DESS key security system was introduced in 1995 by BRP SeaDoos have utilized three different protocols for communications between the BUDS system and the vehicle’s on board computer (MPEM or ECU). The model and year of vehicle determines which protocol and hardware (MPI, DESS post interface, DESS post adapter) is utilized to communicate between the BUDS system and the vehicle. In chronological order, the three protocols are DESS, 947DI and KW2000. 
DESS protocol is used on 2-Stroke carb and pre 2004 RFI skis to communicate. On these skis you must use the DESS interface AND DESS post adapter to physically connect to the DESS post on the ski. 
947 DI protocol utilizes the communications port which is typically located close to the MPEM ,you connect via the 6 pin grey Deutsch diagnostics plug the same as all later models , This protocol is utilized on all DI SeaDoos. 
KW2000 protocol , more commonly known as CAN  (Control Area network) is utilized on all models of 4-TECs  , this is a much more upto date communications protocol and is widely used in the automotive industry , diagnostic connection is via 6 pin grey Deutsch diagnostics plug usually located near Battery ,  the 2005 only
RFI SeaDoos also use the CAN protocol and connect via 6 pin diagnostic plug.
Other than I-Control equipped SeaDoos, you must use the DESS post interface connected in series between the MPI and vehicle to program keys regardless of protocol.
BUDS software is updated periodically throughout the year. These updates include support for new model year products, updates to the diagnostic software and firmware updates for select BRP models. For our customers who have purchased kits from us updates are available free when they renew their licence keys , for customers who have thier own systems software updates are provided at nominal charge when they purchase/renew their licence keys.
BRP have now introduced the "letter' designation system for defining the different software for each model , please see the link for a chart explaining this. 
BUDS Program Designation System
For ease of explanation, the BUDS software has two fundamental levels of functionality as it applies to SeaDoo and Sportboats. For the following explanations, the words basic and advanced are used to distinguish between the two levels.
The basic level allows just that, basic diagnostics and access. The basic level applies to 2-Stroke carbureted SeaDoos and Sportboats. Functionality in the basic level include DESS key security management, timing adjustment and general ski information such as ID#’s, Run Time, Purchase History and Last service info. You can not change the run hour history. You can change the number of hours since last service and the rental hours.
The advance level applies to RFI, DI and 4-TEC skis. In addition to those items in the basic level, you can adjust the TPS (throttle position sensor), monitor the engine while running, activate various components on the ski, read and clear faults and view history of the ski which includes: last 30 seconds run time, minimum and maximum sensor readings, lifetime limp time, RPM lifetime profile, and parts replacement. 4-TECs have some additional functions to the above. The most dramatic difference is the ability to flash new firmware to the ECU and 2006, and newer, display gauge clusters. Beyond that, the 4-TECs have some additional features to enable functions such as trim or bilge pumps and binding the gauge cluster to the ECU.
Licence keys:
We can provide licence keys for any MPI-2 units , either genuine BRP units or our own ,we can provide licence keys in
 1 , 2 , 5 or 10 year lifespans depending on customer requirements and for ALL BRP product lines:
SeaDoo PWC , Seadoo SportBoat , SkiDoo, CanAm ATV, CanAm SSV and Spyders.  
There are different levels of BUDS access beyond the normal dealer level key . These levels in order are:
Police , Rental , Dealer , Development , Engineering  & Megatech.
As you might guess, these alternate access levels provide either more or less functionality in the BUDS system and not available to dealers  , we can of course provide any level licence key & lifespan required!!
The Megatech level has the most functionality and is really the only advanced key we bother with , Megatech Electro of Canada is the name of the company that was part of the BUDS development, Hence the level name Megatech. Similar to how the key code controls what product line a dealer has access to, the key code determines if the above levels are accessible as well so a Megatech key is used with the standard BUDS software , it just opens all the features & functions!!, please see our page on megatech licence for more information and some very interesting screen shots!!  .