different belt drives R170 230K and question about Wapu

Hello, it’s condensing. I’m probably going to bring the SLK to me next week or the next week, which my colleague offered me. There’s something pretty bad in the front of the air compressor (metallic rattles/circuits). I suspect either the magnetic coupling of the air compressor or the complete compressor. It’s going to show up. If I’m already there, then there’s completely new belts and pull-off/spin rollers. The front belt (for Lima and air compressor) is available in different variants (1330 mm and 1873 mm). Looking purely optically, I can hardly imagine that the front belt should also be nearly as long as the rear belt. Can anyone confirm the 1330 mm? I mean, I could of course measure the old belt when I use the car. but wanted to prepare/inform me in the best possible way. Maybe one more question: The car is year 1998 and has (real and understandable) 90,000 km down. Leave water pump or make right with it? Greeting Jürgen