My wife's 1998 D2 looks decent inside and out and runs good. It has 185K miles
Purchased in 2007 with 122,000 miles for $7,900.
The PO put a more than $5,000 into it over the previous year. including a bunch or engine leaks (head gaskets, pan, etc and a recent T-belt service at 115,000 miles
I purchased at "CARS" warranty for $550 covering 36 months/45000 miles
At 130,000 miles the transmission was rebuilt and covered by CARS. My co-pay was about $600.

The good:
As mentioned it runs good, rides nice, not a hint of cam chain adjuster clatter, no oil leaks, tranny shifts perfect. NO CELs,
Doing the math, my wife has put 70,000 in 13 yrs.Other than tires, brakes, couple control arms and normal maint. it has not needed much.
Tires and brakes are all relatively new (last 5,000 miles)
I had the ABS module fixed and reinstalled 3 yrs ago
My wife loves this car and doesn't want anything newer like a D3

The bad:
It's due for a T-belt soon.
It has a small oil cooler coolant leak leak It will definitely need a thorough flush because I put in some liquid aluminum that is holding the oil cooler leak to about a 1/4 cup leak when it sits overnight.
I fear the fuel pump is on borrowed time but I have a "rebuilt" pump (replaced the core pump, cleaned plastic housing). I had this from a 2000 A8 which got a new pump
The AC won't hold a charge
Cruise control doesn't work (probably the stalk lever)

I could do the work myself and have done most maintenance over the years myself but at 75 yrs old, it's a bit much for me.

Would you dump money into this or look for another D2 (97, 98,98,2000) in great shape with all of the major things done

 

I'm in the same boat with my 2001 (see a few threads down) or I was until I determined I needed to fix it. Can't sell as-is, can fix it for $500 plus some effort.
Once fixed it'll be hard to sell for reasonable money so I'll be in a different boat.

In your case if you can afford to sell it for even $950 and move on, then that's what I'd do.

Finding another D2 in any kind of OK is not easy, maybe an A8L could be found that's not too ragged-out. Then it'd probably need some work:
replace the lower valve body and put in a TransGo valve
replace the fuel pump,
replace the serpentine belt, idler and tensioner roller
be ready to do the axle shaft seals and CV joint boots (do both when either is needed)
...maybe a few more things.

I'm not sure what alternatives there are, different set of problems I suppose. A big issue IMO is that there are very few SWB A8s, and the S8 is not as comfortable on our local pothole farms.

 

You're in a tough spot, but I agree with audijim113. As good as the D2 was, it's time to move on. The cars of today are much better in all aspects. If you want to stay in the Audi family, and D-bodies are not what your wife wants. Take a look at the A6. They are about the same size as the D2. The A6's ride will be as good if not better than the D2's, and the A6 will have all the modern amenities that people appreciate.

The D2s were great cars, and their body style will always look great. But, their time is coming to an end as daily drivers.

Good luck with your decision.

 

+1 this.

I'm in the same spot with my 2000. What I have noticed is that unless someone starts a company that sells restoration parts for these cars, I estimate that in the next 2-5 years, most replacement parts will be NLA or only available from used parts sources.

I'm sure timing belts and kits will still be around, but have you tried looking up some of the special formed coolant hoses??? Specifically the two hoses that connect to the fire wall and feed the heater cores. Places like Autohaus and ECS tuning still have a lot of stuff, but more and more I see "No Longer Available". Even Genuine Audi Parts is starting to list a lot of items as NLA. So, from a maintenance perspective, I would seriously take into consideration how much longer the car has before you hit a dead-end on parts availability. Otherwise, for the die-hards, engine compartments will probably start looking like Rube Goldberg contraptions(not that they don't already).

 

I'm 99% decided. Got a quote today from a shop where I've had work done before and satisfied.
Shop owner specializes in foreign cars, mostly Audi
He owns several Audis, including a real nice D2 his daughter drives (bummer, he won't sell it to me)

Quote::
Complete T-belt job
Oil cooler pipes, seals, etc (shop has done dozens of them)
Replace fuel pump (using my "rebuilt' pump"
Secondary O2 sensors (getting CEL for them)

$2500 total

 

That is a good, reasonable quote for the work involved...I bet you can't buy another car remotely close to this stature for $2500...fix it, continue loving it...