2001 SLK200K; oil & filter change is easy even without the suck thing. There's a conventional-enough drain plug in the sump, reached by dropping the plastic undertray beneath the motor. it's more convenient to use the suck thing, I suppose, but it's even more convenient to just let the dealer do it - however, DIY is a snap.
I needed 10mm socket to drop the undertray, and I used a conventional socket for drain plug - yes, it's a hex-head - or could use a spanner.
I needed a specific tool to pull the oil filter; GSF have the monster socket type. It's easy enough to do; note which way the old filter element comes out - mine wasn't the same at both ends, so be sure to install the replacement the same way round as the old one.
My engine let about 4L of oil out; I replaced it with 4L of 5w50 Mobil 1 and have the level midway between low and high marks on the dipstick at this time, having added no more.
Engine intake air and cabin vent air filters are also an easy change, plus you get the chance to clear all the old vegetation &c out of those areas.
So far, the only special tool needed was the special filter socket - about £10 at GSF. Other methods may work; I can't speak about those.
A plug change, or at least inspection, is a bit more esoteric because DCX don't use hex-head bolts to retain the coils. There's one per cylinder and they live above the plug; my 2.0 engine had male-form torx-head screws, needing torx E8 socket to allow me to pull coils off. After that, a long slim plug socket was necessary, but that's commonplace for any 4v engine.
So, in summary; the oil, filter and plug service was a breeze! The local dealer wanted about £250; they always have very polite people, smartly dressed, working in comfortable, clean, serene surroundings, and it's easy to see how.
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