The Guideman has come to MazdaRoadster!! And he has the fix for your SLOW windows!
Teflon Replacement rollers
If you have slow windows most likely your stock rollers are cracked and the grease in there has transformed into a gel/paste or wax over all these years, common for all miatas. If your windows are slowing down its usually the rollers failure that leads to the other parts working harder and then just dying on you.
This is how MOST look on the older NA cars, they get saturated from the grease, and self destruct over time.
FWIW Mazda no longer sells the guide rollers unless you buy it installed on a new $200 glass window
Here is a photo of the stock one vs. the aftermarket Teflon version, any questions? ](*,)
Ill bet once you open your door up this is what you will find.
(Left) = Stock, (Right) = Teflon Version
If your windows are starting to slow down do yourself a favor and get a set from the group buy!
Group Buy is here --> http://mazdaroadster.net/showthread.php?2299