Interesting. A 17 RWTQ/ 20 RWHP gain is nothing to shake a stick at on a N/A 2 valve. I think $700 is very reasonable as well. Hopefully it is cast well and fits well.
I personally know Brian at THR and he has some of the badest stangs around! I lived in El Paso, Tx when he first opened up his shop and was part of our car club.......very knowledgable guy.........he was also one of the contenders in the 2v modular shootout put on by MMFF a while back...... I Know alot of people that have work done by him so I will try and get some details...........