Reuben

hi there

i have a 96 legacy GT wagon

i am wanting to mod it heavily but not sure where to start, thinking to single turbo it with a WRX or STI turbo and STI top mount or front mount it? but unsure wether those turbos will fit to my ej20r?

also when i am driving hard the check engine light comes up(only in 3rd or 4th gear in second turbo) and wont let me use turbos, but it goes away when i turn the car off for 10seconds or so.and lets me use turbos again. what is this?

sorry for long post but i have no idea where to start.

thanks heaps