My brother-in-law has these on the 306 we dropped in his 88 GT. He's got a Vortech on it too. We should be firing it this weekend or the first of next week. I'll let you both know...
I have them on my 92LX. I dont really have much to compare to but it is a bunch faster than my 89GT was with ported GT40's. And the heads and intake are really the only differences in the two cars.