Brett-wv14

Would one of you awesome guys like to give me some quick info on basically im getin my decat up pipe fitted this weekend im goin to take it to a mechanic, ive read various posts and am i all covered in thinking all i need to do is get a bolt to fit the hole :s and a resistor and leave the rest in the mechanics hands? Anything else i should know or help prep him for?

Bare with me im still learning along the way.