sounds like you need to do some serious homework. For your year the 3kgt came in 3 flavors; Base, like you have, with the 163hp SOHC (meaning single overhead cam) engine. SL, with a 222hp DOHC (dual overhead cams). And the VR-4, which was a 320hp, twin turbo DOHC with all wheel drive.
basically what stealthee's saying, it that you'd be better off either just selling your car and buying a VR-4, or swapping out your entire engine for a VR-4 engine.