STi engine swap in SVX?!?!?

I am sure the question MAY have been asked before - basically I want to do a engine with tranny swap - I think I can get everything done for less than 3k which I think is reasonable. I wonder if - : May not be an STI but a WRX modified engine with tranny- either or

1. decreased weight of engine will increase performance
2. better tranny will increase performance
3. beefier turbos

Well you guys get the drift - let me know ASAP please plan to have this done BEFORE Dec.