Don't even mess with the 20/22R series motors. Go straight to the 2rz/3rz if you want a 4 banger. If that 150 hp isn't enough - The go with 5vz 3.4L (190HP) V6.... If you want to get crazy with a turbo (240 HP +) then a 7MGTE is where you want to go, but I doubt you can fit that under the stock sami hood and grill. Personally I don't like the 7M's, no low end torque for crawling and picky head gaskets!
I'd recommend a 3rz - then again I'm bias..........
