when the time comes for the next generation to be optimized to result in an overall excellent product from the start.
I have to say, I don't think development timescales are involved at all.
The CS models do not contain any significant engineering upgrades (oily bits), yet are priced at a hefty premium over base models - and since the CS modes don't contain any significantly different oily bits, the changes in performance have come from adjustments to existing components/programming, or simple bolt on changes, such as semi-slick tyres. The M4 went into production in early 2013, the final specifications would have been locked in place in late 2012 at the latest. I struggle to believe these changes justify the price
or the length of time it's taken to roll them out. If they were interested in optimising the base performance of the M4, I'm sure they could have applied the technical changes at the LCI, and carried on with a small uplift in price.
What I think is more likely (IMHO), is the CS models are simply a move to position M3 & M4 models in a price bracket above that where they really belong. They
need to create a perceived difference between the base model and future CSL models in order to justify the whopping price difference they will charge for it.
Previously, many hot M3's have been used to homologate racing parts, that's not the case with the F8x generation... The GTS and CS are simply brand building exercises, and at this stage it's one that I don't believe is backed up with a genuine value proposition. They need to do it, because people need to get used to seeing 100k+ M3/4's in order to get over that mental hurdle.
The fact that they can't talk about any genuine weight savings, despite alluding to them in the press releases is pretty embarrassing to be honest, and evidence of just how superficial that this performance level of M car is. They are simply creating a position for future models to occupy.
Just my opinion... I'm feeling cranky today.
... having said all that... the M3 CS is going on "Matski's list of 700 Bimmers he'd buy if he was a multi-millionaire."