I remember when i had my rs...to many false hopes and dreams...i know you've heard this a million time but...theres just not as much potential with the 420a than there is the 4g63t. and lets just say that you did turbo your 420a, you couldnt boost any higher than 10 psi without haveing to build ur motor from the ground up.I'm still learning all there is to know about the 4g's and from what i've learn i can make my gst and 11 second car with stock internals...just my .02