If you want "comfort and space" then get a P38, I find the D2 a bit cramped inside. If 7 seats are of importance to you though it would have to be a D2, although the rear seats sacrifice the rear luggage space , so a bike rack is the go. Best to have a bike rack anyway as bikes inside cars are a sure way to wreck interior trim.
Sure the P38 can have issues with air suspension (bags, height sensors, control module), but that can soon be ripped out and put on traditional coils (kits readily available with a plug in module so the ECU is happy). For $25K you'll get a good one as well, so look for low km's and service history. There's a lot of talk on here about slipped cylinder liners, this seems far worse here in Australia than it is in the UK, and is directly linked to cooling system inadequacies in such a hot climate as the system gets older. If I bought a secondhand P38 the first thing I would do is replace the expansion tank (they split), replace the radiator with a nice new one and replace the heater core (they leak), with the cooling system in tip-top shape you should have relatively worry free motoring from the 4.6 lump (or the less stressed 4.0).
The best advice as stated above is to get out to the dealers and drive all types though.

