I want to do some upgrades to my car but keep it naturally aspirated. It's 280hp stock. I'm looking to get around 350hp. Does anyone have any suggestions. I was thinking cold air intake, chip work, true duel exhaust maybe even better brakes and suspension.

 

It will be very costly to make a NA, 350whp engine. As far as I know, it has only been done on a few cars. You will most likely have to up the compression, change cams, do some head work, use aftermarket tuning software, etc.
You will spend twice as much money to get to 350whp than just bolting on a turbo or supercharger and getting 400whp, IMHO.