best way to add 50hp?

NYBladeZ

$1500 is a bit on the low side, to achieve maximum gains he will need more than just a catback but HFC (which cost more), test pipes or long tube headers (most expensive most gains most noise). You're looking closer to $2000 plus install. I recommend getting a quality installer or it will cost you more in the long run.

If you simply want a little more life in your car best bang for the buck mod is either more aggressive gearing or a set of HFC's/test pipes.

Weight loss is usually overlooked but makes a huge difference, I'd be wary about gutting everything from the trunk though, it will make the car more tail happy.

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2009 Carbon Fiber/Red 370z aka Trish: Sports Package, Meisterschaft full catback, Fast Intentions Longtube Headers, Injen Long Tube Intakes, UpRev Tune: Sold
2008 Lotus Exige S Club Racer aka Bella, always leaves me smiling