I wouldn't think that it's necessary. It's not like releasing the belt tensioner is hard, so you wouldn't really be saving yourself a headache by doing it now. I'm not even sure of anybody having a bad water pump on their vibe ever on these forums.
While you have the belt off,it's a good idea to check 2 things on the tensioner.Check the pulley itself,to see if it wobbles back and forth or up and down.Then also check the hydraulic shock to see if it's leaking.I have to change mine after I get it back from the body-shop,and I might do a "how to".
June '07 VOTM Sept '07 MOTM HCVO /HCMO The Red Devil
its easy to changed the tensioner pulley....but the will have to unhook the engine mount to raise the motor up so u have room to get in there at it.but u will have to be careful when u raise up the motor that u dont misaline the cv shaft like what happened to me......now my cv joint clicks all teh time.
LOVE THAT VIBE 2003 Satilite Silver auto.......188,000kms.2006 Chevrolet Trailblazer White 4.2 Inline 6 291hp auto.........156,000kms.