I have owned the B&B's on my 930 now for 3 years. I have driven non-stop (except for fuel) from the East Coast to the Midwest and back again with no problems. I think the "cracking" issue is an old issue going back more than five years ago. Just be sure and use the factory turbocharger mounting bracket so the turbo isn't just supported by the header flange.
The GHL had issues of their own regarding over-boost with their smaller diameter header to wastegate pipe. The wastegate could never bleed off enough energy to prevent an overboost during WOT events.
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, 8:41 R&P