Possible CV Joint Replacement

I have a 2004 VW JETTA with 34,000 miles on it. I just bought new tires less than 1,000 miles ago, had them balanced, and the works done to them.

I brought it back to sears where I had the tires installed, and had them re-balance them. Because they have said that with VW Tires, they are unable to put the standard car weights on the tires because of the design.

However, I was told by a colleague that it may be my cv joints. Because when I go around corners, or am driving at a high speed I have vibrations, and almost rubbing noises. Should I take it to a mechanic to have them investigate, or should I just go ahead and replace the cv joints myself.

My fiance is a mechanic in the Coast Guard, so i'm thinking that he migh be capable of doing this task. Please tell me if i'm way over my head.