I got my parts through ACS, and did the replacement and that went real well. ACS provided me with an RMA number and I sent them back. It was 99.5% good. The only down to it all was that after waiting about a month to hear anything on the RMA, I called them, and a couple days later the credit went though. When I got the credit, it had a note that they were giving the credit based on the vendor reimbursing them, and that should the need arise, they would charge me later if for some reason they didn't get reimbursed. So it wasn't a 100% in my case, but so far in the end it's worked out great.
The gear swap is easy, but if you're not familiar with mag work, I'd say it's probably even MORE important for you to just do it yourself, because it's the perfect opportunity for you to get the parts, and work with your local A&P and have them teach you about internal timing, and adjusting points and everything else. Depending on how many hours you have on the mag, you may want to pick up a set of points too, btw. So I'd say use it as a learning experience. People need to get involved in their engines, so they better understand them.