The AP brakes were added in 02, that is one of the improvements I was referring to.
They were added in 2000.
Yes, the AP Brakes are really that important. The car is under-braked with the Brembos. Hardware is good quality, it just doesn't stop the car as well as the AP setup. The AP setup can be retrofitted, but they're fairly expensive. I believe the last time I checked they were around 4k.
00+ have all the "issues" with liners, etc. worked out. I would focus on those cars unless you come across an earlier car you're particularly smitten with and the owner can either document a liner job or evidence that it has zero issues in that regard.
Things to check-- all part of any decent PPI, which you really want to do:
1) Leakdown and compression check. If the numbers are not within 5-10 psi for each cylinder, run, don't walk, to another car.
2) Check that the heater/ac work properly. All sorts of little valves and stepper motors that can go wrong, and are hidden in the bowels of the dash or behind the rad. Not the end of the world if you have to change one, but be aware of it before you buy.
3) Check that the car runs reasonably cool and that the cooling fans cycle. Should read 80-90 deg. C on the gauge while cruising, 90-100 in traffic or giving it the beans (on the stock rad).
4) Check that the gearbox shifts smoothly and reasonably quickly.
5) Check for OBD codes. The cars are fairly notorious for evap and o2 sensor codes. This can be a problem if you're registering in an emissions-nazi state.
6) Check for any obvious oil/coolant leaks. Pay particular attention to the rear axle seals (where the CV shafts enter the transmission) and the turbo oil lines.
7) Check that the central locking and cobra fob work as advertised. Failure to lock/unlock can indicate a toasted CDL module, which is an amazing PITA to get at (though easily replaced with an aftermarket alarm and relay setup). Make sure you get the alarm resistor (small stick you plug into the port behind the shifter) with the car.
8) If equipped with OZ wheels, check that they are round. The OZ six spoke wheels are very easy to bend on the inner rim given the width of the barrel and position of the spokes.
9) Note any misfires or "popping" from the exhaust while idling, particularly if only coming from one bank (this is harder to note on cars with a stock exhaust). It can indicate a coil/plug wire issue, which suck to fix.
10) Check roof panel for leaks. If equipped with glass roof, check for chips, glass shards in the frame area. Check that both roof brackets function properly and are tight.
11) Check that none of the shocks are blown. Note any oil/grime on any of the shock bodies, or any "bouncy" wheels while test driving.
Things to change/replace once you get one:
1) Replace radiator with aluminum unit. Doing this will probably require making a new hose for the oil coolers, as I've yet to see a stock one that wasn't effectively welded in place and needed to be cut to remove the radiator pan.
2) Exhaust. Stock one sounds like garbage, and the stock cats ARE garbage. Replace with high-flow metallic cats, or air.
3) ECU. Upgrade to the 'has torque' map, or red if you plan on dumping the cats and want to make with the go-fast.
4) Clean out your headlight bucket drain holes before your first big rain storm with the car.
5) Safety wire the throttle cable end at the pedal. Having that thing pop out is decidedly un-fun.
6) Chances are very good one or more of your gauges will be loose in the binnacle. Remove the offending gauge, wrap the threads on the housing with teflon tape, and reinstall to fix the issue.
7) Replace the craptastic Renault coolant header tank with a quality aluminum unit.
8) If you really want to drive the snot out of the car, as it should be driven IMO, look into a stronger gearset for the transmission. There are several options available.
9) Replace the horrible Cobra alarm with a decent aftermarket unit. I highly recommend keeping the old unit so you can smash it with a hammer. It's very therapeutic.