I searched some more and the final answer is yes and no.

By searching the springs in the catalogue of Suplex (http://www.mladov.ru/katalog/suplex/..._2008-2009.pdf) I found out that the rear springs are identical, yet the front springs are not.
However, I used the Suplex part codes to get the dimensions from this (Dutch) site: Veer vooras SUPLEX 19347 | MijnAutoOnderdelen.nl
Note: this spring is the correct N/A front spring, SRT = 19348 and rear = 19219

Weird thing about suplex though is that the rear springs are identical between the N/A and SRT. Is this correct? Front springs are a LOT thicker (1.5mm) and lower (25mm).

I concluded that the SLK320 springs (19202) are higher (7mm) and thicker (0.2mm). So they should fit, yet you gain a higher ride height since the total length is longer and the spring is stiffer (at least I assume the materials used are the same thus thicker equals stiffer).

I got DOT3 pads in front so I could win about 8mm in height. Yet I donīt know if that would drop the car enough to cancel the lift of the SLK springs. So at this point Iīm leaning towards the (more expensive) Suplex 13947 springs because I don't want the car te be any higher. Rear springs should be a direct fit.


edit:

See attached photo


Could anyone measure their N/A or SRT springs in length and diameter? Then I can double check if these springs are the correct ones.