I have been in colorado for the last 2 years and cant say that I know of ANY toyota v8 specialists in this area. There are a few in CA but I dont know of any in denver/colorado springs. Im from CA but go to school out here and its frustrating. I order everything from the west coast and must fiddle myself.
What mods are you considering? You can order a set of headers online and then modify the rest of the exhaust through use of a muffler shop. Should be around $1000 for headers + pipes + mufflers.