I would install a performance converter, the engine will run better with a converter and it will keep your truck legal. Since your adding an intake, you might want to think about a performance muffler also. Your correct the 2.2 is slow to say the least but a high flow cat along with an intake and performance muffler will help to make the truck more efficient.
__________________
2000 Chevy Blazer ZR2
Performance Mods: Numerous
Suspension Mods: Some, but not enough
Exterior Mods: Just Right
1987 Buick Turbo T Dark Red
Low 11 sec sleeper
.030 4.1 block, PT6262E, & other odds and ends....
My Cardomain