OMC had problems with their 1st Generation of Direct Injection Engines(FICHT). I had a 98 150 FICHT, and though it never blew up, I always felt it was more of a case of When it would Fail, not if it would Fail. Mine received all the Upgrades(reprograming the ECM and new Heads), and later a newer complete Powerhead. As the Warranty was about to expire and any further work was going to cost me money, I traded for an I/O. During the pretrade Inspection, the Powerhead, with about 45 hrs on it, already had a Scored Cylinder(Neat little Score, the tech wrote).
The 2nd Generation were Called RAM Injection and most of the Bugs had been caught., but the problems put OMC out of Business.
Bombardier of Canada bought OMC and eventually released the 3rd Generation, which is E-Tec, which have proven to as Reliable as anything else on the market.
XD 100 is BRPs Premium Oil, and is a Synthetic, and is formulated to reduce and remove the type of Carbon that is formed by Combustion in a Direct Injection Engine, which is a much Harder Carbon than produced in a regular 2 stroke. As mentioned, if the engine ECM has been set for XD100, then only it can be used. Myself I would use XD100 at the TCW-3 setting just for the extra Detergents. It is only 7% a gallon more than XD 50, Brand Name Jug at my Dealer.
As for 3rd Party Oils, well you pays your Money and take your Chances. Most oils are not formulated for DI engines and TCW-3 Oils were a Major Contributor to the problems with the FICHTS. I remember that Chevon Techron and and OMC/BRP Carbon Guard were recommended Additives. Maybe if the 3rd Party Oil Marketer were to cover any Powerhead Failure, I might consider them, but without actual Documentation and Proof, No!
