I personally would try to buy from the same dealership just for the sake of the relationship. Again, just like any business, I would ASSume that they will gladly work on a car sold by anyone, but might be more charitably inclined if an issue arises and you have given them ALL the business for that purchase. Perhaps give them the opportunity to meet/come close to the lower price at another dealership?
nate
******* If you can develop a good relationship with an honorable dealership, that has to be the best situation.
As you suggest, I've never seen a dealership turn down anyone for service.
Some years ago I had REALLY bad luck with Pontiac dealerships in Houston (referring to service). In those days, you could call the zone representative and get help or advice, which I did. He pointed me to a couple of dealerships which had good reputations and fewer than normal service complaints. Honestly, these dealerships didnt do much better, but I finally found one of them that would listen to me and the very long standing problem was fixed.
The dealership had some older mechanics who knew what they were doing, didn't "flat rate", and were proud of their work. I praised them to the service writer, who made some snide remark about them doing a good job but not putting out as much work as the other younger mechanics.
As you can tell in some of my posts, this was one step along the way which soured me on dealerships and GM. When a person did a good job, he was "low rated".
Not much later, I bought a Buick which shortly presented problems. It would die when I took my foot off the accelerator - at the most inconvienient and dangerous times.. I returned it to the dealership a number of times, but always got the excuse from the shop manager that he couldnt find it if it were not broken...meaning intermittent. I asked him to send a mechanic to ride with me and I would SHOW them what was happening.. He wouldnt... I asked him to check the TSB's on this, and he promised me he had already done that.. Then I called the zone representative.. Within seconds he knew the problem- a run of ECM's with faulty semiconductors - and authorized the replacement. There WAS a TSB on it.... Within minutes the owner of the dealership called me and apologized, and the shop manager called me, complained, and threatened me.
It doesnt make much different where you buy. It can make a lot of difference what you buy. And it can make even more difference where you take it when you have to have it fixed.
Sorry for the rant