I recommend Ted Taormina.
http://www.tedtaormina.com/
Ted's built a number of Superformance Cobras, and I own one of them now. Ted's got my car running like a top, and has gone over another car of mine (Gallardo) as he is also a Lamborghini specialist, aside from knowing Cobras inside and out.
I'm particularly impressed with how he tuned my engine, it is a 521 stroker with a fairly radical cam, rollers, mechanical lifters, and it handles traffic, heat, driving around at 1500 RPM just fine, but it screams to the redline :-)
Ted's also the nicest guy I've ever worked with, and he loves Cobras!
-- Gordie