[element]

I'm looking to buy a 2005 Roush Stage 1 Mustang. The only work done to it is visual enhancements and an exhaust system that I assume adds 20-25 more hp, bringing it up to 320 or 325. If I get this car, I'm going to want to do work to it, starting but not ending with a cold air intake system, headers, probably a wider throttle body and so on so forth. If I do this work, do you think that i will decrease the value or increase the value of the Roush because it is a limited edition car?

[GTRaptor]

Do it, it will not reduce its value.
If you get the parts from Roush it might increase it in the long term.