Air ride system was converted to coils using one of the numerous kits available for our cars.
Water leak to passenger floor. Easy fix, just needed to reseal the air plenum for the HVAC system. The MN12 guys (T-Bird/Cougar) had fits with this, and the Mark VIII is loosely based on the MN12 chassis, this is one of the gremlins that carried over. Mark VIII is known internally as FN10.
Other than that, fault-free!
Engine - the all-aluminum Teksid-block 4.6 is a beast... once you get it over 3000 RPM and the IMRC's open up, you'd better be paying attention! Below that, it's a little sluggish, thanks to the 3.07 gears, small engine displacement (only 281 ci), and high curb weight. You can't outrun the laws of physics! With a good amount of revision, this is the engine that went into the 1996+ Mustang Cobras.
Suspension - Early Mark VIII's rode a little stiffer than the later ones, in part due to a different (inferior) front strut design. The early front struts like to bind up with age, swapping for '97-98 struts fixes this. Be on the lookout for leaks if you're planning on buying one, and familiarize yourself with the system. It's easy to diagnose issues. I went to coils because I got a killer deal on the kit and because, as a college student, I needed the reliability. Cost no object, I would have kept the air-ride.
Handling - Generally good for a car of its size. The steering is very quick to respond. Oversteer is a throttle-poke away if you disable the TC! Maneuverability, especially in parking lots, is surprisingly good for a car its size. Decent turning circle. I'd say it's easier to maneuver than the Mark VII was (and I'm very familiar with both cars).
Braking - 4 wheel discs with standard ABS. It gets the job done. I had a few "close calls" and was saved each time.
Interior - Terrific quality overall, best I've seen in an American car -in my experience-. Just be aware that the early VIII's featured climate control buttons that were easily broken - you push them down and they don't feel like they've done anything - you push harder, they break!
The stock JBL sound was fantastic. Loved the moonroof. The Autoglide seats will give your rear passengers fits though LOL (AHH my legs!!!) Watch out also for wear on the driver's seat side bolsters from people sliding in and out. (Got lucky with mine) Driver-centric dual-tier layout is awesome.
Styling - I showed a picture of my car to a girl I know when I bought it, and the first question she asks is: "Is it new?" Not bad for 13 years old! Guys, the ladies will love it. Timeless good looks!
Fuel economy - not that bad for what it is - usually I got ~18 MPG around town, and I saw 27 on a longer highway run. Gotta try to keep your foot out of it, though easier said than done!
I owned my VIII from June 2005 to August 2006. I shouldn't have sold it, and still have sellers' remorse to this day. It needed the typical VIII fixes, like a front-end rebuild (right around the 90-100K mark), and it was more money than I had at the time, so I sold it for a Bonneville. What a mistake! Sold that as soon as the title came for my Grand Marquis - which is OK - but I spent $5K between those two cars to fix $700 worth of repairs on my Lincoln. I was a fool.