I replaced it mostly because it was looking a little 'green' on some of the fins, so I figured some serious leaks and such aren't too far coming.
Plus, with the age of the thing(17 years and going!) It was probably a safe bet that it wasn't flowing or cooling as well as it did when new.
So, for only $100, I bought an over-seas replacement (all metal, though!) and it fit like a glove!
While I was at it I replaced all the belts with some good 'Dayco Top-Cogs', all new hoses (with a wire in the lower!) and clamps and such.
The car is noticeably cooler now, and stays at a constant temp instead of going up and down as it did previously.
I am very concerned about this 'overheating and bad head hasket thing' I have been reading about here.
I have only had the car about a month or so, so I'm doing the 'catch up' thing with all the specific little details about these cars that trouble them.
I am actually pretty close to being paranoid to even drive the thing until I get the exhuast replaced with the cat-less down tubes and cat-back system.
I have been driving it daily for about 2 weeks now, but I rarely let it ever get over about 5 lbs of boost on the gauge. That takes a real light foot. Mostly, I try to keep it totally out of boost.
Every day it seems I find another annoying little detail that the previous owner neglected. I spend a couple hours searching these forums learning stuff, a few minutes fixing it...and the car just keeps running better and better!
Right now I am suspecting that I will replace the motor mounts, for the idle is not as smooth as I think it should be. The motor doesn't 'jump' in the engine compartment, but they are 17 yeats old, right? What can it hurt?