I've said it once on this forum and I'll say it again. Part of affording a luxury item is maintaining it, not just buying it. I pay close to $2,000 a year just to insure my watches and I pay about $400 every 5 years on EACH watch just to have it factory serviced.
Losing a full day to do this kind of service on a Porsche myself (even if I knew how) would cost me more than letting the dealer do it.