hmmmm... here will be some good links if u wanna do some reasearch if u dont wanna take our word for it...
www.2gnt.com ( this wil be ur new best friend)
www.hahnracecraft.com ( everything u need to boost ur 420a)
www.howellautomotive.com ( awsome internal upgrades for ur 420a)
www.slowboyracing.com ( i noticed the other day that day sell a bolt on 420a turbo kit with everything you'll need)
p.s. if you stay here in mitsu long enough to learn about everything and what not you'll probably here about the "brothers"( aka rob and dave) they have worked on 420as before but primarily work on 4g63's but there other brother angel takes 420a jobs from what i last heard