I have thought about this as i bought my w203 230 Sport Sedan...

They are made by Lysom, and Eaton...from my understanding some have an electronic clutch, and some do not.

Most parts are servicable - it's just a matter if you want to take it apart.

When my dad and i installed my Eaton M90 into my w123 - we tore it apart, replaced all bearings, and redid the seals...also replaced one other part

if it is rattling then i would bet it is the front coupler. what it does is takes the wear and tear - it is designed to...it is a tattle tale. it transfers the power from the pulley and splits it to the front gears for teh rotors...uder light load and no boost it is sloppy and noisy - as you load it - it is forced into place and silenced...

superchargers are extremely simple things...extremely well engineered and extremely well manufactured...

I bought a front coupler (because my cheapo M90 i bought off ebay for $100 was rattling) and a bottle of GM supercharger oil for very little money and rebuilt the nose cone of the supercharger...then we replaced all the seals and bearings - so for about $200 i had a running m90 pushing 8psi...

GM and Ford recommend replacing the oil at i think 60k, when i asked my MB dealer they said don't worry about it - good for life...I don't believe that...

Good luck - check PotomacGerman
Jake