W900 questions

About to dump my shaker columbia in a couple months and pull the trigger on a w9, looking for input from owners as to w9-specific things to be aware of/watch out for when looking at a few of these trucks. Best looking trucks on the road imo, and I've been inside a few of em but never driven one so idk about certain quirks they may have and whatnot. I pull dry van and I usually run the midwest and south, never northeast, so I don't care about the wider turning radius. Looking to spend up to about the $50k range, preferably closer to $40k though.

Here's the things I know for sure that I want in the truck:
1. 1990s model year (so I can go back to paper) preferably a 99 just so it's the latest one of the decade while still being exempt
2. Cat 3406e with fairly recent overhaul
3. 13spd
4. 3.55-3.70 gear
5. Standard sleeper, no flat-tops

What differences were there in model years during the 90s? Can't seem to find any specific info on the whole internet regarding the aesthetic and functional differences between W900 model years. Which suspension should I want, ag200 or ag400 or something else I'm not aware of? As for the 3406e, what is the better one between the 2ws and the 5ek (or 6nz if that was available in the 90s which iirc it wasn't until 2001)... Also I've heard that the hoods sometimes shake at certain speeds, wondering how common of a thing this is, and also wondering about the fit and finish of the truck in general. I've only ever driven Freightshakers so a sh**ty ride quality is all I've ever known or experienced, not to mention the constant squeaks, rattles, and wind drafts coming in through various nooks and crannies all over the truck. I'm figuring that even a bad W900 has to be a world better than an average Freightliner. And what about the wiring, are they known for any electrical issues? Also, how much worse is the fuel mileage for a cat-engined largecar vs an aero/plastic truck, is it a noticeable difference? My columbia (Mercedes motor) usually gets no better than high 6s if pulling very light over flat ground, or as low as 5.3-5.4 if pulling 45k over some hills. I can't imagine a largecar being much worse than this, aerodynamic or not, but correct me if I'm wrong.

Basically for $40-50k I would think that'd get me into the territory of VERY well maintained 1990s w900's that have had recent overhauls and have good interior fit and finish, does this sound like the appropriate price range to expect a lot of W900 for my money?

 

Rugerfan you're right I could make do with a lower gear. I was just thinking 3.70 because my buddy has one with his 3406 and I like the way the truck pulls, maybe something in the 3.30s-3.40s more appropriate though.