Never had a problem with my GruppeM
I did notice the first 15 miles or so after installation the car was a little jerky,
But after that there was a noticeable difference in pull from the engine on WOT,
I do have the ESS tune however and I remember Roman saying the tune adapts to new mods such as intakes and exhausts so that could have been what happened,
Now the car runs smooth and I love the look, sound, and feel of my GruppeM
I actually coated the inside with gold foil to block heat, but I think its more for aesthetics as gold foil generally goes on the outside of things, Still looks unique
(also replaced the blue silicone coupler that comes with the kit to this black one as suggested by Ron Stygar, The blue was just so out of place)
