It would be a perfect daily drive to compliment the 350Z.
You've already touched up on the one issue that plagues most of the E36es. The water pump. Just make sure the water pump has metal impellers instead of plastic ones. If you're not technically savy, have a mechanic check it out.
Another weak point is the rear shock mounts. On the E36es these are hard to check, since you'll need to remove the rear decklid to access these. Also, check the subframe mounts underneath the car...This is another notorious weak point.
Outside of those areas, the E36 is a freakin' TANK mechanically. Expect electrical gremlins though, with advance age they may rear their ugly heads but will not likely prevent you from being able to enjoy your car.
Other than that, if you find a car in good condition for a good price, it's hard to beat BMW's steering feel and handling characteristics.
"Bench racing" about track times driven by professionals are like a bunch of nerds arguing which Princess Leia is hotter, the slave Leia or the no-bra jail-bait Leia. No matter how compelling your argument is, the plain and simple fact is, none of you will EVER get to hit that.