rally isn't about power. obviously, you haven't done much rallying, if u like what block does, asesome, better have 10,000,000 in ur bank account and alot of spare time. you learn to drive a slow car fast. the 2wd championships are very often won by 1980's VW's w/ no more than 100 whp. learn to handle the car. save up for a rally coilover setup, then put on some skidplates for protection. you'll be fine that way. but if you truly wanna get into rally, go for the right mods, not the powerfull ones. you can't run boost your first year anyways in rally. (correction, 99% of people can't)
if i were you, i'd stay 100% stock, throw on a QUALITY set of mudflaps (not universal ebay crap) so you protect your paint, then get a skid plate. go to some rally crosses and get your skills up.
terminator v8 in an SVT focus (soon to be boosted @ 20 PSI with a 2.9 L Kenne Belle on Corn!!!
(750 rwp and low 10 second focus, here I come!)