420A motor- replace timing belt tensioner?

I'm doing a valve job on a 420A ('97 Eclipse). I have no history on the
engine, so I'm doing a timing belt and water pump replacement while I am
there. The odometer says about 90K miles (and Carfax seems to agree). What
else do I really need to replace in the timing belt system? The rollers
sound unpitted and feel tight. Does that buy me anything, or is there
sometimes undetectable damage to rollers?

Probably my biggest question is whether to replace the timing belt
tensioner. This is a "get it running" rebuild of a stock engine. I think
I'll be happy to get another 50-75K miles from it. How much risk do I take
in reusing the existing tensioner? Has anyone come up with a leakdown test
of sorts with a heavy weight for an extended time?

Also, who is a trustworthy supplier for the parts? Who has the best price on
the tensioner? Do I care about the brand of timing belt for this kind of
rebuild?

Thanks in advance,
Frank Kerfoot