I'm planing to pick up a set of Nitron R3's for my GT3 from my boys here in Taiwan German Motorsports.
they seem to have very good quality i've seen these in person. should be a great choice for M3's
Past: Gintani stage3 M3
present: Porsche 993, 964,997.1 GT3, Panamera Turbo
waiting to be delivered 2015:
Porsche 991 GT3RS