Should I sell out? Please Advise!

[BBBurban at aol.com]

I am growing weary of chasing problems on my 1990 90q20v.  I have no garage 
to work on it in and winter is coming.  After going to the Stealership today 
and paying $43.94 for four bolts and sleeves for the exhaust springs bolts in 
front of the cat talked to an Audi tech and he tells me he would never own my 
car because of all the problems they have (crappy door locks, window 
regulators, the infamous "bomb", electrical and lighting woes, ect)  and he 
highly recommended the next generation.  Including a very nice S4 I was told 
about.  Went to look at it today at a local used Audi / VW dealer.  It is 
being sold privately but the used car dealer said they would buy my car.

S4 :

the last owner has only owned it for 2 years and put these things into it.. 
so most likely wasn't beat on too hard

Upgraded turbo, exhaust manifold, and 3" stainless exhaust 
drive shaft has been rebuilt
chips for fuel and turbo management
very clean car...  128,000 miles (timing belt coming up in 20,000)
asking $16,000

My 90q20v

Everything seems OK but faint smell of antifreeze when first running the 
heater.  It does go away but not a good sign

the bomb is bad

A/C inop 

oil leak... possibly rear main seal but not sure.  Most likely a valve cover 
gasket as well.
148,000 miles (timing belt due)
They say they will give me $4000 for it

Wouldn't mind owning a car like this (est 385 hp) but the purchase price is 
kinda scary.  Two biggest factors are will this thing last for another 
100,000 miles without majior problems and are there hundreds of little 
problems waiting for me (window regulators, electrical switches, ect).  
Looking for a car as dead on reliable as my 87 Honda Accord but as nice and 
fast as this is.  

Any and all opinions please 

TIA   

Hank 90q20v  (*for now)