I had some cracking on mine in the same area but it was after a few hundred passes and a lot of hot street driving.
Brian had it fixed and back to me quickly. He reinforced it a bit but in a different way then you did.
My car was also running a bit rich, which brian told me kills headers.
DAILY DRIVEN: 92 GT
306,9,5:1,AFR 185s,RPMII,xe264hr,ProMagnum rockers,turbonetics 66S,bg kit,METH,Flowmaster catback,Accufab race 75mm,pro tube,60lb injectors,255lph walbro BAP,ac delete,no smog,full MSD ignition,mark fan,3G alt,TKO600,spec stage 3,alum flywheel,3.55s