I've been shooting e-mails with him regarding my gt40's, really awesome guy to deal with. I'm still undecided on what to do which is the hardest part. You won't regret getting just a port and valve job. I have seen many pictures of his work and have heard nothing but good things, so I'm trying my best to give him my business.
On a side note, "I don't provide flow numbers cause they're so misunderstood", he said. So he'd rather speak of gains between 30-50hp which I think is pretty bad ass.
But first of all, decide what you want to do, and then talk to him. I won't provide a price either, that's up to Thumper.
FWIW, if you just want to get into the 12s, sell your gt40's and buy the Thumper ported e7's.