You know if you trade you will put a bunch of time and money into the 98, which btw is the fun part...but then you'll feel attached to it and all these concerns you have with the 2000 might come back.
I understand the feeling you are having, very much, but if you figure you will never sell the 2000 then all those concerns could be some what less. If you get a ding have it fixed. Do you show the car?
In the end if you have the money put a 3.4 in the 2000, the wife can't complain about an extra car
. That extra power would be awesome in the car you really love...but then again you said that wasn't that important.
Sounds like you need a break from the garage queen feelings and it would be nice to have something to drive the hell out of for a while...that IMS time bomb would bug you though so again like I said you would be doing a lot of projects.
What is your heart saying, you know it will hurt to let the 2000 go, you will only feel good if it goes to someone that will car for it.
Flip a coin, if you don't like what it came up with then you'll know your decision. Your 2000 'S' probably won't last long if you go to sell it