No, I install my pacesetter headers last week and I fell an improvement also. The acceleration feels better than before. I didn't think it was going to be as good as it is because it seems that a lot of people are unhappy with them (headers), but for me and my auto gs I thinks it was a great mod.

White 1997 GS (auto)
Short Air Intake
Front Strut Bar
Arospeed Muffler
Pacesetter Header
Bosch Spark Plugs
17 ADR Ryver on Supra Kumho Tires
3rd Gen Altezza Taillights(center covered to match car and stripe)
Euro Front Bumper Lights
Hyperwhite He