We had a 1999 TL for two glorious years before we lost it in a freak flood here in Michigan. (It was five inches of rain in a couple of hours.) I really miss that car (it was the deep emerald pearl color), and I think we dodged a bullet on the transmission, as it still had the 4-speed auto vs. the 5-speed (from 2000+) that grenaded regularly.
Thing is, the fix for the 5-speed auto has been staring everyone in the face for over a dozen years now, and hardly anyone does it. Don’t repair, rebuild your TL’s transmission. Instead, get the 5-speed auto trans out of a 2007 Accord. It’s the new, redesigned unit and they are much more solid. The few I’ve read about who have replaced them with these newer 5-speeds have had no failure issues at all. I guess all you need to do is swap a few sensors or solenoids over, and it’s good to go. It bolts right up since the V6s are all J-series engines.
The seat heater in the driver’s seat never worked when we bought the car, but I was able to remove the leather and repair the wire. The issue is that it burns through from the heat where it crosses over the metal supports. Simply soldering in wire in a few spots got it working nicely.
We did replace the rear struts, but, the car had probably 190k miles on it at that point.
The radio worked, but that system sounded terrible. I was almost ready to put a new system in it when the flood claimed it. Glad I didn’t bother.
The only other issue we had was the usual Honda evap error code, and all of that is located underneath closer to the gas tank. (My kiddo’s 2002 Accord has the exact same setup, since it’s essentially the same chassis.) That was another on my to-do list. We did lose a couple of the ignition coils but again, by nearly 200k miles, those usually go bad anyways. After literally hundreds of millions of sparks generated, they are bound to wear out.
As for tires, we put Kumhos on it and never had an issue–they rode smoother, gripped better and were quieter than the Michelins that were on it. Totally transformed the car, and they wore evenly up until she drowned (where they became flotation devices).
The 1999s still don’t have a bulletproof transmission, since the 1998-2002 Accords also had a lot of failures, my kiddo’s car included. They are very similar, from what I understand. Hers (B7XA trans) has had the harsh 1-2 shift ever since we bought it dirt cheap a few years ago. It hasn’t gotten any worse, but it’s annoying. With all the other problems now (the rear beam rusting through, the leaking gas tank, the exhaust that someone “fixed” by welding the entire thing together…even the cat…), it’s not worth replacing it. I did try cleaning the solenoids but it got no better.