I think Peter Newman (yellow mk1/mk2 G60?) uses a Klaus box- and obviously uses aftermarket management.
I'd have thought he's making 250Nm+, but I don't know how often he rebuilds boxes.
From my spreadsheet I made for a WL Motorsport box for sale, here's some typical 'Berg' ratios, control tyre is 540mm diameter (175/60 R13)
G40 ATV
Final Drive: 3.333 Tyre Diameter (mm) 540.2 Actual Speed:
Gear Ratio Engine Revs(rpm) Output shaft(rpm) Driveshaft(rpm) mph
1st 3.455 6800 1968 591 37.36
2nd 2.095 7000 3341 1002 63.43
3rd 1.469 7000 4765 1430 90.46
4th 1.098 7000 6375 1913 121.02
5th 0.851 7000 8226 2468 156.15
5th 0.851 3000 3525 1058 66.92
WL Motorsport ATV
Final Drive: 4.710 Tyre Diameter (mm) 540.2 Actual Speed:
Gear Ratio Engine Revs(rpm) Output shaft(rpm) Driveshaft(rpm) mph
1st 2.500 7000 2800 594 37.61
2nd 1.880 7000 3723 791 50.02
3rd 1.520 7000 4605 978 61.86
4th 1.290 7000 5426 1152 72.89
5th 1.160 7000 6034 1281 81.06
5th 1.160 3000 2586 549 34.74
That's pasted a little squiffy, but last column is speed in gear @ 7000rpm, 81mph in 5th for the WL box!!!
Part of th reason there's nothing that good for G40s, is the Berg Cup boys can make do with stock(ish) boxes, they've got minimal torque from the screamer n/a motors