Small addendum, the last quoted figures indeed seem to be correct.

Just received message from friend who's a technician in a Porsche garage.

Here are the ranges for 997 GT3:

Range 1 : 8400-9200

Range 2 : 9200-9400

Range 3 : 9400-9600

Range 4 : 9600-10.000

Range 5 : 10.000-11.000

Range 6 : >11.000


--

M3 CSL / Alpina D3 Bi-Turbo Touring / RS2 Avant / GT3RS Kermit