PLEASE GIVE ANY ADVICE OR GUT REACTIONS YOU MAY HAVE TO MY POTENTIAL TRADE!

I need a wagon with its space, here is what i can swing:
trade my awesome 92 AT/PW/PL 138K sedan with cloth interior for an 89 wagon with virtually the same amount of miles on it, AT, probably PW and PL, CD, etc.

MINE GOOD: records from when i purchased it 10 years ago with 97K. new master cylinder, tires, this and that...everything that could have gone wrong already has, and it runs EXCELLENTLY. AIRBAG! No collisions, very straight, even, etc. No foreseeable repairs needed for another 50K miles i imagine.
MINE BAD: no stereo and ugly hole in dash because of needy individual expropriating it.
Passenger window switch pretty bad but will work from the master switch on the drivers' side.
Center console plastic pretty broken from friends humongous dog standing on the cheap shitty plastic which broke.
Most things made of same plastic (map holders on the doors) are royally broken (WTF is with that cheap plastic?)
trunk leaks (must be weather stripping)
small dent in front port fender
missing trim around front starboard bumper
missing trim on two lower panels, one upper trim (the shopping cart bumper)
windshield wiper switch only has two settings, the lowest setting is now a duplicate of the medium one, and to turn it off you gotta time the switch with the downstroke of the wipers (fun but distracting)

HIS CAR: haven't seen yet, but is at his mechanic. No past records of maintenance. But is being professionally worked on, etc. Has roof rack. No airbag. Vinyl seats (not going to be Tucson friendly come summer).

If his car seems good and all that, can i expect the same mileage from it as I get in mine? (roughly 23-26mpg highway, and yes it's an automatic!) Is a wagon categorically more valuable than a sedan? If i repaired, say, the weather stripping on the trunk and replaced the center console plastic myself (>$40 worth of materials from the import auto store i figure), would that be a 'fair' trade, or do you figure my car is still worth a bit more?

I know it's impossible to truly know all this without seeing his car for sure, and i'm worried about it being a lemon, but if it passes smog and has no outstanding tickets etc. than convenience dictates i should just trade away and say goodbye to the airbag, which i will sorely miss.
thanks for any advice/gut reactions you may feel inclined to write here