If you are going to remove the flywheel, then why not replace the seal too. Just know that you are looking at the possibility of mechanics error or bad seal (even OE) and could see a leak. What is life without taking chances, right?Well, I have to say, it seems like half the people here think it's a good idea to replace the seal and half don't. And everyone makes pretty good arguments. So I'm a bit confused. Also, I talked to two well recommended transmission shops. One said, if it's not leaking not to replace it, but mainly because aftermarket parts are low quality. The second said, it's easy to do, he always recommends doing it, after more than 100k miles it's probably starting to dry out, he can get the part from Mazda, and he's never had one come back leaking. The only consensus in this thread seems to be to use the Mazda seal, if it's replaced.
Regarding the flywhell, the two transmission shops I talked to also both said they would pull the flywheel to resurface it, in which case I'm thinking maybe I should just buy the Luk flywheel for $72, which is cheaper than what they're charging for resurfacing.
I typically do not replace seals unless they are leaking, even at high mileage or age.