Transmission question.

If I wanted to change 5th gear of my S1 transmission with a LS one, what part(s) would I need ?

I never did it but I'm sure a gear puller would help a lot.

oh... i'm not going to do the work myself, I wanna be able to go to a shop with the stuff and tell em what need to be done.

and have an idea what the parts cost... not to get riped.

How hard is it to do your own tranny work. Theres something rattling around in the Si 5-speed tranny im about to put in with my ZC and want to take a look inside myself to see what it is, but ive never done any tranny work before. Anyone know if its a big pain in the ass? Theres a shop here that wants to charge me $75 just to take it apart and look at it. Would it be too hard for me?