Can you REALLY feel the difference? I had them on my Grand Prix and couldn't tell the difference. Don't know if G's are the same. I don't do a lot of track racing except for drag racing but if it REALLY makes the pedal considerably firmer then I'll buy them.

 

The older the brake lines that you are replacing, the more difference you will feel.
Upgrading the fluid will also make a big improvement, if it hasn't been done for a while.

 

A fresh bleed will make the pedal firmer. Try that first, and then do the lines later if you're still not happy. Comparing SS brake lines with fresh fluid to rubber lines with old fluid is not a valid comparison.

That being said, with the 5AT Coupes it could make a bit of difference since some folks feel that the pedal in our cars is somewhat soft (though I've never felt that way with my Brembos). The Brembo coupes have portions of the brake lines that are steel braided, IIRC, so I doubt the benefit would be that great on mine, but I could be wrong.

 

I need to change the fluid anyways but don't want to spend $100+ on a set of lines that won't make me feel any difference.