One of the idlers sounds right. I had one of my idlers that was like a half a fucking inch shorter than the one I took off. I ended up spending 3+ hours riding around looking for a bolt that would fit it and was only threaded so far down the bolt, I think I ended up finding a slightly longer bolt and cut it to fit, probably the biggest PITA of the whole job when I did mine, lol. Good luck.
EDIT: Here is the post I made on IWSTI when I changed mine and the problems surrounding the idler.
After putting the water pump on, I realized the smallest pulley is just slightly different from the original (someone mentioned this earlier in the thread). Where the bolt sits in the original pulley it's recessed about a half inch or so, but the new pulley has the bolt recessed about an inch. So when you go to use the same bolt, there ends up being a half inch of play that the pulley can move around (this is not going to work). So I had to go to 4 different stores looking for the bolt, and the best I found was a bolt that matched exactly, yet it was about an inch too long. So I had to buy a hacksaw and cut the bolt to get it to fit. I'm sorry I don't have any more specific specs on the bolt as I just found the one that was closest and never wrote the specs down. I know it's a M8x1.25, but that's it. It's very hard to match because the bolt needs the first 2 inches to be smooth (unthreaded) cause that's where the pulley sits, but the rest needs to be threaded. Your probably going to have to pull the original bolt and use it to try to match when you do this, or you can make sure your pulley is an EXACT match as the original.