I know there are some strong opinions for and against on the effectiveness of the GT stiffening kit. My question is, assuming that it definitely works to help stiffen the chassis, is it a good addition for a street car that will never see a track or is it unecessary? Car will have an engman kit. A 3.2 six is slated for the car.

The Engman kit should be your first step and sounds like it is so you're off to a great start. If that's all you did, you'd probably be happy enough. Next week point I have noticed is the part of the long that goes between the engine compartment. I'd do braces there long before the actual GT kit.

Don't forget about the long kit from Brad Mayeur. It is a 10 ga steel kit that adds probably the most support of any package I have seen.

Good point, I spaced that one, never used it.....yet.

The first thing I noticed after installing my first Engman kit was how much the opening for the engine bay changes/flexed. Couple little cross braces up high fixes that one.