Fumes in 924s when windows are down
 

When the windows are up there are no fumes. When The windows are down I get gassed by exhaust fumes. It has something to do with the rear hatch seal. Is it a bent frame or just the rubber thats missing a 2 inch length?

Sounds like you just need a new hatch seal. Very common and an easy fix...although not cheap for the seal.

Been there. Just replace it with a new one, dont bother with a used one.

try adjusting the hatch pins first so that there is a tight seal, also look for holes that are not plugged in the hatch floor area, also check the tail light seals if need be. is the exhaust in good shape?

Hmmm
 

The seal looks fairly new , like the previous owner replaced it, Except a 2 inch section is missing, like they cut it out to make the seal fit. The exhaust is in good shape. What holes are there to plug in the hatch floor? How would I adjust the pins to make a tight seal?

get some material and fill in the 2 inch section. I have found the overlooked seal is the one that you can see from the outside when the hatch is closed and looking from the back of the car right above the lock, it runs across the back of the spoiler, adjust the hatch pins so that this seal is doing its job, there are some plastic plugs in the hatch floor area that you can see with the carpet removed as well as the drain tube holes, make sure the tubes are in place.
presoak the pins in wd40 if they are hard to turn

Cracked / broken tail light will also cause this. Especially if it is the drivers side.