How does a custom exhaust really work? You go to a performance store and they just weld you some pipes and you buy a muffler (ebay) and they install it for you? Do they make the pipes just to the cat conv.? Or do they do the whole thing? I think 500-600 for something that gives you about 5 hp, is not really worth it. I was thinkg of going stomung, but I dont know the price of that, so I cant even think about it. How much would the pipes cost? And I was thinking about going to turbo later on, could I just get 3" pipes now, or would that decrease (flow) performance? I dont really care about performance too much, because Im not going to bother with i/h/etc because it wouldnt get me anywhere on my (Automatic) GA. I just want a nice looking and deep sounding exhaust.