Whats the best sounding exhaust if i want to keep my cats and should they be dumped or no and whats the best tuner..

 

If you are talking about a handheld tuner they all suck.... A dynotune or street tune is what you want.
Exhaust note is very subjective but IMO dumps are WAAAY to loud in the cabin and are best for a drag only car..... I love the way my Hooker Aerochamber CB sounds but with my setup it can be embarassingly loud sometimes. It was stock volume before the H/C/I went on BTW. Magnaflow I also like and if you want louder Borla. Keep in mind mods like LT's and a cam can TOTALLY change the sound so plan for your mods in advance...

 

Theres so many exhaust systems for our cars, it just depends on if you want mellow, great sounding or obnoxious. I personally wouldnt get dumps, you will smell it with the windows down. I went with the GMMG catback & love it. Its not cheap($800) but its 304 stainless & it fits perfect. It can get pretty loud if you get on it, especially with LTs & cam but IMO it sounds amazing. Its not quite obnoxious like SLPs LM1 is. As far as tuning goes, a good dynotune, maybe mailorder tune for a few boltons or just buy tuning software like HPtuners or EFI Live. If youre serious about tuning it yourself, I highly recommend getting this book on tuning. https://ls1tech.com/forums/pcm-diagn...order-now.html

 

I would say the best sounding catback exhaust for the GTO is either Borla or Corsa but they aren't cheap. If you want to replace the cats and go with headers/high flow cats/exhaust system it will cost even more. Below is a good website with all the exhaust systems that are available for the GTO.

Not all handheld tuners are bad, I have the Superchips Cortex and it's a great tuner. It increased the hp almost as much as a dyno tune, plus it's cheaper and you can change the settings anytime you want. They have specific tunes for all the popular cold air intakes up to 93 octane so it maximizes power, and you can also adjust shift firmness and other trans settings. It's simple to use and they give you free updates for as long as you own the tuner. It will also log data of various engine parameters and log acceleration time in seconds or MPH.

http://marylandspeed.com/pontiac-gto...back%20Exhaust