I'd stick with the '87, you've spent the money on it and know what to expect. Sure, it's got some minor issues, but those aren't gonna run you $9,500. The older Brougham is a much simpler car, much less to break down, cheaper to own in the long run. But on the other hand, the deVille is a lot more modern and has a lot more toys and gizmos and stuff, which is a big attraction for a lot (myself included). As far as styling goes, I'm all for the Brougham, inside and out..I love the long, formal, upright elegant lines and boudoir interior, it's classical Cadillac elegance at it's finest!
As far as drivetrains go, the Northstar will stomp all over the 307 as far as any sort of performance measurement goes, but I believe the 307 in the end is cheaper to own and maintain (yes, I did see that the N*'s HG's had been already done so that's a big bonus for that deVille) they should post similar mileage around town, but the Northstar will get much better mileage on the highway.
As far as drivetrains go, the Northstar will stomp all over the 307 as far as any sort of performance measurement goes, but I believe the 307 in the end is cheaper to own and maintain (yes, I did see that the N*'s HG's had been already done so that's a big bonus for that deVille) they should post similar mileage around town, but the Northstar will get much better mileage on the highway.