I have one car with M030; i bought a car with new replacement Bilstein HDs and OEM springs installed; and i have PSS9s in that 2nd car now.
I would go M030 (match the springs to the shocks) or - follow me - PSS9s.
The Bilsteins (HD, yellow) did not, as i recall, raise the car. Bruce - do you agree? But note the OEM Bilsteins are twin-tube, the HDs are monotube HP gas.
The M030 is a great, agile setup. yes, a bit harsher than stock, but very good. Works on road, works on track. Not very low.
The PSS9s are the surprise. Set soft, they are in some ways more comfortable than M030 or even stock.
And they are adjustable to whatever height you want. Nice, IMO.
I don't follow your comment about mixing M030 with some unknown springs - the whole point of complete kits is to get critical damping engineered as a system. By mixing, you lose this - trust me, it rarely a good thing. Since the kit comes with a complete, matched set - use it. Note there is a difference in ride height between ROW M030 and M030 ( i have the USA spec). The USA spec is only about 0.3-0.4" lower than stock, but ROW kits, new, are becoming unobtanium and i could not wait.
I suspect true OEM shocks will be costly at the dealer, but they are, well, stock.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com