2000 A6 C5 2.8L Avant with 250k miles. Hoping to get another 25k or so out of it before buying a new one. 100k since last timing belt change. Still runs well except for two issues:

Issue #1: Runs hot: on highway gets up to 1:00 on the coolant gauge (110 C according to Vag Com) at 60 degrees out. Worried about summer. Already replaced coolant, CTS, fan clutch, radiator, overflow cap, confirmed electric fan runs on high, passed pressure test. Heat works great. My best guess is the thermostat opens, but not all the way, even though that isn't the usual way for them to fail.

Issue #2: Burning oil smell when using usual oil. Assuming it's the passenger rear cam chain tensioner gasket and plug. Also some seepage showing in spark plug wells even though I had valve cover gasket not long ago. Running 20w50 instead seems to have solved these for now. No problems starting in winter fortunately. Considering changing the cam chain tensioner gaskets.

Question#1: To keep costs down my plan is to do the timing belt/water pump/T-stat job myself for the first time. I've put it in lock carrier service position, but not gone further. So I'm figuring out where to buy the necessary tools affordably: locking bar 3391, locking pin 3242, cam chain tensioner 3366. (Assuming/hoping the crank and cam seals are ok so as to not need those tools. Planning on borrowing a sprocket puller from Advance Auto.) My guess is I'll never use these tools again. So are the low priced knockoffs on Amazon good-enough? Prices range from about $200 for a 3391 and 3242 at Blauparts to $20 for a "PMD Products" set on Amazon, and everything in between.

Question #2: Do I try changing the valve cover gasket and cam chain tensioner gaskets as well since I'll be nearby, or given that the timing belt job will be the biggest car work I've ever done, keep using the 20w50 and not overwhelm myself with trying to do that too?

Thanks!