Dunno what a mall amount might be but after 50 years with all sorts of minor differences, different tyres etc. between different model Europas in the interim, it might not transfer easily between one car and the next because the Europa is generally also fairly sensitive.
Frankly, beyond the 47's and the small number of race prepared cars out there, I reckon there hasn't been all that much exploration of the development potential.
As was noted, when the TC/TCS came out, many S2 drivers discovered better high speed stability with the TC front splitter. I put one on and found the same thing.
Later on I discovered the rear springs had started sagging by about 1-1/2". I took advantage of the opportunity and had some 2" spacers machined up to try out. It turned out the slightly higher stance at the rear seemed to enhance the handling overall. Bear in mind this is a Type 54, so it's more in line with stock 46 height anyway. That then got me to wondering if the TC splitter could be deleted for no loss in stability and a regain of the extra drag.
I've only tried a few things within the non adjustable nature of the car but high tyre pressure seems to make it 'tippy' everywhere. I've tried front toe-out and it definitely improves sharp corner turn in on the track without much affecting anything else. On the drive home, however, it's noticeably a bit darty, so not everything transfers as we might expect. Probably best bang for the buck on the track was fixing the bump steer.
I still think we aren't taking much advantage of the entirely better modern tyres and probably can't without going all the way with stiffer springs, roll bars and everything else to get the car handling flat as a tack.
I dunno. My Honda Civic daily runs very firm & flat with 215/45 -17 tyres.
I often wonder how much grip you could get out of a Europa running something similar.
In sedate suburban driving, most wouldn't know the Civic is front wheel drive.
Of course, there was that time in the rain cruising on the freeway at 110KPH when we came across a sheet of water running across the road. The half worn tyres aquaplaned, the car was under cruise control and the front moved sideways. That was interesting.