Turner Test Pipes with stock rear section is a great way to fly, not to loud but sounds amazing WOT and on down shifts, combine that with a tune and you're looking at 40+whp/30+wtq gains.
Just did mine the other week
2012 BMW S1000RR — Racing Red/Alpine White
2009 BMW M3 Coupe — Alpine White on Fox Red, DCT - ESS | Turner Test Pipes | Macht Schnell Stg 2 | OEM Performance Splitters, Spoiler & Mirror Caps | 3D Design Diffuser
2003 BMW M3 — Carbon Black on Black, 6MT - DPE | B&G | K&N | JL AUDIO - Sold
1995 BMW M3 Coupe — Cosmos Black on Black - Sold