Funny thing I noticed about the stock 420A and a built one was when add the turbo, you really do feel the boost kick in. From what a reliable source has told me was because of the stock compression being higher. I dont know if I agree with that but that may be a possibility.
Now if you are smelling gas I would check for a fuel leak somewhere. Rich burnt fuel smells but it doesnt neccesarily smell like gas unless you are pouring 1/2 your tank out through the exhaust. My first instict is to say its the injectors being too large and I am basing my information on the numbers located here :
http://www.2gnt.com/www/corbin/chooseinj.html
When I get home tonight I will look up some other things I have what other info I have that may help.
See... I did those numbers also. And my result was 550cc injectors. I have a set of those too. So, i'm going to try putting those in. The thing is that i don't want to loose fuel in the long run and I don't want to keep on swapping back in forth. Ohh And another thing.
LS1fever tuned street tuned my car when i had 625cc and prior to having a "blow bye" But i think i'm going to try it anyways until i can invest in a port fueler by Hahn.