Banging it off the limiter is no problem as he would have set the limiter safe, I set my soft cut to 7300rpm with hard cut at either 7500 or 7600, can't remember at the mo, as engine had 200,000 miles on it, all on original bottom end, and still cracked 40mpg without trying too hard, though not on std ecu, best thing I did was bin that, and the "bind" to certain people with the software for it to change etc, I get three maps for £280, but don't bother with closed loop as not needed imo(and others), I run a soft build up of boost for the wet etc.
"safe" would depend on so many things, even some big names wouldn't know a decent map if it bit them on the rs(imo), turbo wear would obviously be a consideration, as would general engine wear etc.
It's your car at the end of the day, but seriously consider a G4 ecu swap, it's a cracking deal from people like danny.
tabetha