Indeed, the SLK32 is hardly the same car as the 320.
Engine is reinforced in numerous ways, increased lubrication, oil cooler, all forged moving components, bigger injectors, different cams, new ECU, etc.
Transmission modified and new TCU.
The basic pumping volume of the
SLK230 supercharger is light for even the M111 2.3L, only producing about 8 lbs of boost.
On the 3.2 L
M112, the 230 supercharger won't supply enough volume for boost, it will actually be an air restriction, unless spun way beyond its design limits, which will shorten the life and fail, possibly spectacularly.
Adding the SLK32 supercharger to a 320 is not a good engineering path, even for an experiment.
It will just damage an otherwise good engine.
The best solutions for a
SLK320 performance improvement is a tune, and cams, if one can still find a performance shop or specs for 320 cams.
Take the secondary cats out of the exhaust (if not already failed), this will increase a few HP and sound more crisp. Keep the resonator, it will drone badly around 1800 rpm without resonator. (just loud is not good)
HP won't come cheap, but the 320 could be bumped up about 40 HP or so, from 215 to around 250 ish.
Suspension components from an SLK32 could be fitted to the 320 to improve handling.
Springs (factory Eibach), swaybars and front shocks.
If not OEM (
Sachs) shocks, use Bilstein B6 front and B4 rear to mimic the SLK32 suspension tuning.
Happy top down spirited motoring, in a tuned 320.
R