8800k limiter in my MC2 with the map, sk2 inlet oem head+valve +retainers,sk2 tuner stage1 cams, power higher with the cams from 7.6k rpm oem>8.2k rpm peak
Use mine to 8.6 now and again but dont like to push it on the valve train tbh.and dont take it to the limiter at 8.8k as run out of power by then and needs a gear shift,but have done <but you have an R head i know>
so
<<<<Dependent on condition of you C4 ,>>>They are very popular for turbo for a reason and very strong .
mine has 112k always run on Magnetec
rev limiter at 8.5 oem & redline 8.2k standard so recon 8.8 k not far from 8.5k oem.
Bigger tyres on to adjust gearing maybe ,FD ?
the c4 pistons may not deliver power well at 8.8k so as above change gearing with tyres to keep in usable power.and a safer working max rpm. its a long way from home!!