It is not such a simple question, as with the S4RS you will get not only the Ohlins suspension but also a newer, arguably sportier but also arguably less practical bike.
On the suspension front: the Ohlins fork is very good, IMO, for road use on stock settings although the springs may feel a bit soft if you are a hefty type or aggressive on the brakes. It seems very sensitive to damping fluid viscosity and these days I insist on the recommended Ohlins stuff.
A downside of the Ohlins fork is soft, low-stiction seals which can and probably will prove troublesome.
You can probably upgrade your fork internals to match or exceed the performance of the S4Rs fork, but IIRC a full cartridge kit would cost you $1000 or more plus fitting. (Don't have to go that far of course.)
WRT the shock, you can read about my experience sorting that
here and I suggest that you do. The stock Ohlins shock was IMO poorly valved and unnecessarily harsh. It also used the dreaded twin lock-rings to set preload, and these are very hard to get at on the S4Rs even if you have twin Ohlins C-spanners, as I did.
So, don't buy the S4Rs for the shock, although it is a perfectly good Ohlins unit mechanically and if valved properly will work very well. A high-end aftermarket unit for your own bike would be just as good or better. (Not that I'm saying you won't want to revalve that also: at this level, small changes make a great deal of difference.)
So in sum, if it is just the suspension you want, then for a lot less than €3000 you could have your S4 working much better than a stock S4Rs.
OTOH, if you are not happy with the €600 fix (you don't say what that involves), you could end up spending €2000 on a shock and fork cartridges and then wonder why you didn't get the S4Rs, which would need only a couple of hundred € for a revalve (oh, and fork seals once a year
).
