My feedback is based on my personal experience. It isn’t difficult to spot a set of KW over stock suspension when the car is on the lift - anyone that says otherwise has probably never seen the underside of a car
. Besides that, I always listed it as a modification when booking the car in for a service. So comments that the dealership ‘didn’t know about it’ are a bit silly, I think. I don't normally write long responses, since these are invariably picked apart by others, and I also don't have the time for long debates anymore. Car forums became a bit boring when people stopped modding their cars, in my opinion. I remember the "good old days" when most members had some kind of mod, mostly performance enhancing parts and software and we compared and analysed our logs to determine whose software made the most power, while maintaining safe ignition, engine temps etc. We installed different coolers and compared logs before and after to post some real -world results; added meth and did it again; tested various types of octane boosters with maps with advanced timing settings to compare which pulled the least timing retard etc. Those were interesting times - data fascinate me, but that's the engineer in me and probably not everyone's cup of team - or brew of lager.
I didn't like the standard suspension of the M2 - it was skittish and always wanted to get you too far sideways with the slightest throttle input around a corner. The KW corrected all of this, a major improvement in my opinion. I could have gone for the Motorsport option, which is the same suspension with BMW brand and different colours, but I got the KW for R 5k less, so fitted that.
At the time I asked my parts supplier and the Service Advisor what the risks would be, and both said that BMW would obviously not cover any warranty claims on the suspension - that seemed logical, and hence I drove all the way to Balito to have it fitted by the KW agents for SA.
I also fitted upgraded charge pipes, which I bought from Firi, and the only complaint I ever got about those were that they would take longer to remove and thus added some labour time.
I also ran a JB4 piggy-back setup, which I removed before each service - I never had any issues with that either.
I'm not saying there isn't risk if you modify a car under plan, but the best people to ask are the guys and girls at the dealership, the people that deal with these issues on a regular basis. I know of people that had their plans cancelled - there were such examples and you sometimes saw an M-car advertised on Autotrader, for example, with comments that the motorplan had been cancelled. I don't know the circumstances of these, but that has never happened to me personally, and I've been modifying my cars while under plan since 2006, albeit most of them Audis. The mechanics used to give praise for tasteful mods - my S4 with RGM exhaust and custom cooling with stage 1.5 Revo and upgraded pulley was a hit back in the day.
Times have changed, I suppose...but modding remains a part of the enjoyment of car ownership for me. That said I don't know what I would mod on a new G87 M2 or G80 M3 for that matter - they're quick enough rolling off the showroom floor. Perhaps I would try to figure out ways to make it lose some weight, although it would be an exercise in futility I suppose, and one would be better off accepting that the newer "small M cars" are closer to their bigger siblings than the previous gen models. The same can be said for a Porsche - if I ever find an itch to own a Cayman GT4 or a 9112 GTS, I probably would only look at suspension and/or low-key braking upgrades aimed at improving track times, and leave the rest of the car as is.
OP's car is an F40, so I digress, but if I was the OP, I would reach out to some people that have done this on their cars before, without facing any warranty issues or motorplans being voided. It isn't about luck, necessarily, it is about being informed when making these decisions, and using all resources at your disposal, including, but not limited to, car forums.
I personally wouldn't ever fit lowering springs on a car, as these do nothing to improve the actual handling of the car and may in fact make it worse by reducing suspension travel without adjusting damping of the shock absorber. I would also avoid cheap suspension upgrades - while on the expensive side, a proper set of KW coilovers will make a big difference to the enjoyment of a daily driver without compromising ride quality or reliability.
This must be the longest post I have written on Fanatics, ever, and cost me 30 minutes of precious work time. I hope it adds value, and if not, then at least I had the enjoyment of travelling down memory lane for a bit.
