i would most definatly go with AB Mods, Hes the only one ive seen that can bring the real power out of the Vspec. He has even been in XRC and his regular vspec dominated the Speed version.
The proof is in the pudding. There are alot of hacks out there that promise things they cant deliver.. be careful who you send ur mill to. With AB Mods you have proven performance.

http://www.youtube.com/watch?v=L9JSzc5UVW8