Did you replace your r50 belt tensioner yourself?
 

I'm sure someone's done this and can hopefully provide some how-to help? There's some discussion about changing belts (very helpful DIY pictorial) on NAM, but I can't find anything about the tensioner itself. I'd love to hear what's involved in swapping one out yourself. I've had mine replaced once, but two years later the replacement sounds bad. However, since my belt needs to be replaced for sure, I thought I'd invest in the belt tensioner tool, replace the belt myself and see if I don't hear the tensioner chirping after that (it's occasional, usually in wet weather). That way I can keep an ear on the tensioner and replace if/when need be. I just can't tell if I'm saving myself any money this way. What's involved in replacing the tensioner?