Need Rust Information - Pre-Purchase, What's bad? What's not? Where to look? Options

[matt13421342]

I have had a few Porsches but I am ready to buy my first 914. It is mostly rust free, but if it's anything like a 911, "mostly" can mean "costly" if the rust is in a bad spot. Could anybody tell me what to look for, what's real bad, what's no big deal? It would be hugely appreciated. It's a great car in Maryland so it's not a NE rust bucket, but I want to be safe and avoid big resto projects.
Thanks in advance- Matt

[swl]

we need to put this all together on a tech info or something - it comes up so often.

Adding to Chucks start:

The interior floors are covered with a tar like substance. That can hide some pretty nasty rust. Look for cracks in the tar an go poking with an ice pick. Like any other porsche/vw replacing the floor is no biggie as long as the longs and firewall are solid.

Peel up the interior carpet that goes over the longs and have a look for rust where the long and floor join. Particularly look at the indent for the hand brake handle. Any rust here can be nasty. It starts from the inside and works out. If you see it it is probably worse than you think. Ice pick it.

Rear firewall at both corners of the floor pan. Passenger side rust there suggests the hell hole problem Chuck described. There are interior reinforcing kits that you can weld in if there is minor rust damage to the longs/firewall. Major rust in the longs will kill the project unless you have the skill and patience show in 'digging into hell'.

On the underside check the area around the lift donuts. The rear ones are easily replaced. Forward is part of the floor.

The trunks rust - particularly the rear. Water tends to leak in through the taillights and then sit under the sound proofing pad. Not structural easy to fix (ha - at least if you weld. I don't (IMG:style_emoticons/default/sad.gif) - yet (IMG:style_emoticons/default/smile.gif)

Cosmetic problems around the door striker plate and above the door handle recess of the door jamb. They used some kind of sealer in that area that seems to attract rust.

Gas tank. Hard to tell on a ppi but there is usually surface rust inside the tank. As long as it hasn't perforated it just a weekend's work to renew the tank.

Bottom of the doors.

cowl at the bottom of the windshield particularly around the gasket to the fenders. Haven't read to many threads about that area but I suspect it would be a bugger to fix properly. Look for hack repairs in that area.

who else wants to add to the list?