Having a new Mirage, I get the first 3 oil changes free from Mitsubishi. I don't know if I want to get it from them or do it myself though. When I bought it, I asked the dealer what type of oil they use and the guy said it's a synthetic blend, which wouldn't be 0W-20 from my understanding. I already have way more miles than I would like to have before my first oil change (4000 in a little less than 2 months). I've just been too busy to get it done, wanted to at 1000 miles. I don't want them to screw it up, I've been doing my own for the last 15 or so years. I also don't want to void my warranty by doing it myself (my understanding is it wouldn't as long as I keep copies of the receipts and when I do it).

I am tempted to get the 3 free oil changes through them, but I have reservations about it potentially being crap oil and service.
What would you guys do? And is there any possibility it would void my warranty if I do it correctly myself?