As far as wheels, they are used and I have four fronts, You all know that G bodies and F bodies have the same bolt pattern. I don't have any fitment/rubbing issues and that is with the '79 Trans Am steering box I put in.
I'm not going to go with the GNX fenders, I'm having a hard enough time pulling off the GN clone as it is. My interior gives it away, it is grey buckets out of a Monte SS and black carpet. I have a Monte center console painted black and silver. Some people are fooled.
I have a stock 4L60 (basically a 700R4) in there but it is dying under the power from that LS1. The Regal came with a 2.41 one wheel peel in it and by the grace of God I found an '83 Trans Am with a great Auburn posi and 3.23s at the U-pull-it for $50. I put one of those 7.5 girdles on there and I hope it will last.
Jbreu - I have been on this site for a long time and have read all about your Monte. You are usually spot on with your advice. 514 at the crank should have you in the high 11s. I expect to be in the mid 12s now.