[Xlot]

Beware of poor 928's that are in a poor cosmetic state.

Regardless of PPI and service history, most S4's need a lot of catchup maintenance: (edit: these are just the parts prices for a DIY'er.. you really don't want to know how many paid workshop hours it will be..)

intake refresh = $2k for new FUEL LINES, sensors, gaskets, hoses and various other bits
timing belt job = $1.5k for new belt/sprockets/tensioner bits etc.
suspension = minimum $1k for shocks/bolts/rubber bits

This is all stuff outside the service schedule, but that needs doing after 20 years. PPI's usually focus on making sure the car runs, brakes work, visible leaks, and if you're using a good 928 mechanic, checking crank end play (do not buy an MY84-onwards auto without a crank end play measurement!).

Now all those costs aside - fixing cosmetics is the single most expensive part of owning a 928. You're *much* better off financially starting with a 928 that looks good inside and out and then doing all the catchup maintenance to make it run right. Reckon on $10k to do an "ok" cosmetic job (i.e. reasonable paint, and installing a decent used interior), rapidly progressing to $20k for a good job (better paint, new window seals, re-cover seats).

The flip side is, if a car's super-cheap, you do your own wrenching and read a manual/forum, cosmetics don't bother you, and you just want to drive the crap out of it, then cosmetically poor examples of barely running 87/88 S4's can often be picked up for sub-$5k and make an excellent daily driver for well under $10k total spend.

Lastly - if anything in this post confuses you - you're not ready to buy a 928 yet and will likely get burned. I'm not trying to patronize you - there are some nasty gotchas you need to understand about before you spend hard earned cash, like Thrust Bearing Failure. If you have questions about any of the above - ask and people on the forum will happily answer questions.