I reached out to MSS this morning again to get a copy of their installation guide. The guide they sent is somewhat generic, which isn't a problem necessarily, but a few things concern me about their kit.
The front setup looks great. They provide a replacement bump stop, a shock bump cap for the bump-stop to contact with, a new rubber pad for the flat bottom of the adjuster, obviously the spring and adjuster, and a pair of protective sleeves that go over the adjusters.
The rear is where I have questions... The instructions say to remove the OEM spring seats both upper and lower, and to replace these with flat rubber slip mats on the upper only. The lower end of the spring just sits directly on the lower control arm without any rubber at all. No rear bump stops or shock bump caps are supplied either.
My understanding, is that as you lower the car, the clearance between the bump stop clearance is reduced. More bump stop clearance improves comfort, but also has a negative effect on handling. Less bump stop clearance results in a harsh ride. The whole USP of the MSS kit is their trick stacked spring setup in the rear. If a customer installs and goes for 30mm maximum drop, the M2 could very well be riding on the bump stops at that point.
I emailed MSS and asked them this question, and was told:
The front can be lowered to 30mm +/-3mm so the rears should be adjusted to be 5mm higher than the fronts thus will sit 25mm, so the rear stock bump stop therefore dose not need changing hence why we only provide the fronts.
May I just also add that we do extensive development on all products before we release to the public so want we release is the most effective set for that model.
They did ask me not to share the install guide in case it gets updated, and I've agreed; they'll happily share it if you email them.
Please understand that I'm not intending to be critical of the MSS kit at all. I just like to do a very thorough investigation before I purchase.
The concept of the MSS kit is exactly what I'm looking for - more controlled and compliant ride, with improved handling, and the option to lower between stock and -30mm.
The lack of a rear bump-stop modification leaves me feeling that if the MSS kit is used at stock height, you'll get everything they claim, but if lowered, particularly to maximum, you'll get a pretty rough ride.
I was considering being a guinea pig, but I'm now super excited to hear about
OzWoz' experience. Please do let us know!