Seems like a bit of care and preventive mintenance would have avoided a lot of this, but...

What is a "clunky" shift. Does it flare?

Is the coolant leak from the water pump?

That oil usage is not so bad for a 103 engine. Valve stem seals would probably help. It may be leaking from the top timing cover if you're lucky, the head gasket if you're not.

Try changing the PS fluid and be sure the belt is properly tensioned.

The interior? You have to be the judge.

The fact is, although these are great cars, they are not worth so much any more and a significant repair can cost more than the car is worth.

OTOH, it is an awful lot of car for the money. I intend to keep mine going until they fall over dead because I don't know what I'd replace them with that I would like as much, or respect as much.

__________________
2012 E350
2006 Callaway SC560