Yup.. just the header alone dynos about 28-32 HP gains at the wheel!! Personally I never believe company dynos.... however, I've seen many independant dynos verify the gains. Exhausts on the other hand won't get you much.. probably around 1-3hp max.

For headers you can buy either Comptech or OBX headers. Comptechs are better quality and go for around $1100. OBX are lesser quality.. but still do the job.. and go for around $400.

As for exhausts... there are a few: Comptech, HKS, Mugen to name some. Comptech are the most popular. I don't like the HKS on the TL-S... but it looks hot on the CL-S. Cheaper then Comptech too. Mugen are the cream of the crop.. but also are cost a lot and are hard to find. I'd recommend either Comptech or HKS. He'd be happy with either.