?'s about stock parts on a '91 Coupe

[Duo]

I stumbled upon a '91 240 Coupe yesterday while heading to a friend's house.  I went back to check it out today in the daylight and I must say I'm pretty impressed with the condition of the car for its age.

The exterior...with the exception of a few minor paint chips...is in superb condition.

However...the interior needs some work.  The seats are starting to come apart (no big deal), but the digital speedo and heads up display don't work at all.  

I was half-assed looking for a '91-'93 coupe to make a project out of, but I really wanted a base model.  This one is an SE with all the bells and whistles...the problem is most of them don't work.  

The engine (~150,000 miles) still feels very strong and the suspension is still tight, but I don't want to spend a small fortune just trying to repair the broken electronics.

Does anyone have any idea of how much I'm looking at in parts for the speed and H.U.D.?  

Or...can I just swap in a standard gauge cluster?  Are there ECU/wiring differences between the two?  

BTW...they're asking $4,000 for the car, which is a little more than I want to pay.  If I can get it down to $3,000 and just replace the cluster with a standard analog unit, I might go for it.  

Suggestions/Advice/Opinions?