OP here - just got done doing the second timing belt on my own car this weekend. Car has 170,000 miles. First TB was done at 82,000 miles. There were two things I did this time that I hadn't done the first. First, I converted from the one-piece TB cover to the two-piece cover. Secondly, a installed a new thermostat and housing. I did not replace the front camshaft seal or the front crankshaft seal, as neither were leaking oil. I replaced almost every squeeze-type hose clamp I removed with a screw-type hose clamp. Some comments...
Two-piece TB Cover - I have some comparison pics I'll add to the first post later. The newer style 2 piece cover makes the job much easier IMO. Removing the engine bracket is one of the complaints I hear most from people that have done the job, and having the newer style TB cover makes it loads easier.
Thermostat and T-stat Housing - What a royal PITA! It took me longer to change the thermostat than the entire timing belt job. While I recommend changing the water pump every time you do a TB, changing a thermostat is not made any easier by doing it during the timing belt replacement. They are completely separate jobs that do not overlap. Also, thermostats typically have a longer life-span than timing belts so they need to be done less frequently. For that reason, only replace a thermostat when/if it fails, or if you were already doing some job that involved removing the intake manifold, such as cleaning your intake valves. Conveniently, my thermostat went out (partially stuck open) about 4,000 miles ago and I was already planning to clean my valves after doing the timing belt so it worked out nice. After removing the manifold, you must disconnect all the coolant hoses from the plastic thermostat housing, then remove two bolts that connect the housing to the engine block. For headache-free access to the two bolts, I removed the alternator. Since it's a good idea to clean your intake valves every 60,000 to 80,000 miles, I'd probably just do the thermostat every other cleaning. The code my car threw for the failed thermostat was P2181.
Camshaft Seal & Crankshaft Seal - While some timing belt kits come with a camshaft seal, I would not replace this unless you can visibly see some wet or shiny oil coming from that area. I just did my second TB and both of these seals are holding up just fine. I always have the seals ready, but will not use them. You will never get a seal as tight as from the factory, so do not replace unless necessary. Regarding these seals... "If it ain't broke, don't fix it."
Also completely unrelated, I replaced my fuel hard lines on the manifold to allow a banjo bolt to bamboo fitting conversion for my HPFP. Also did a HPFP stud conversion and replaced the N80 purge valve. Did my second valve cleaning at 170,000 miles. First cleaning was done at 60,000. The valves were much much cleaner compared to when I did the first cleaning, even though I drove more miles before this cleaning - thanks to the exhaust-routed PCV. And there was absolutely no oil that poured out of my intercooler piping, as is always the case when I do valve cleanings on other cars. Tomorrow I'm doing the timing chain and tensioner job for the first time.
-Zach
