The adapter plate allows you to bolt an earlier TB to a later intake, and most people use it in order to put a 04+ Gen 5 supercharger on their 97-03 L67 engine. The L26 TB is drive by wire, yours is cable driven. You could use an L67 TB however, IIRC they have the same sensors and everything. Plus the adapter plate is easier to find.
you can use the L26 LIM, and modify it while you have it apart.
http://www.grandprixforums.net/threa...w-to-Mod-a-LIM
Some of that won't apply, since the engine is N/A, but the first two steps will help if you ever have to pull the TB off and don't want to spill coolant, and prevent the TB adapter from leaking.
Also the L26 heads are slightly better than the L36, so keeping those will be a good idea.
The only other difference between the two is the alternator bracket, depending on which alternator you will use, you will need the corresponding bracket.
There's a few other things, using the aftermarket aluminum coolant elbows that go into the alt bracket, the later design steel LIM gaskets, other small upgrades/preventative maintenance... By the end of this swap, that car is going to be pretty sweet.
