They actually started the new "manual" tensioner on some later production '98s although that info isn't even listed in Vadis for a '98 car ('99 on up only). Replacing the belt on the newer type is actually easier BUT it's also trickier in that there's a tensioner marker that needs to be adjusted to its proper setting by the engines temperature and the pic showing the proceedure is in Vadis, not in print yet. I'd speculate that if not (replaced) and adjusted correctly, the belt might fail and that'd be a major problem so I won't suggest trying it yourself here as if you were to do it wrong, you'ld definately be upset. The newer turbo cars with hydraulic "cam adjusters" get even trickier yet so when the DIY guys decide to try this themselves, they'll be on their own and I'd specualate that I'll be reading about a few disasters. I don't know if Bay 13 will print details and pics on the new type belt or if it's even a good idea IMO but time will tell.
How to tell them apart? It's easy to remove the cover (one bolt) but it seems that the newer "manual" tensioner engines have a smaller 10mm head bolt holding the cover on whereas the older "automatic" types use a 12mm headed bolt.