I am in the market for an ISIS BB for my 2001 Bullit. It has a 68 / 113 now. I will be running a guide. I was told by my LBS that I could run a 68/73 113 BB w/ my guide. I asked if the BB was E-type spec'd (Race Face SRX) "No but it will work". Is it better to find an E-type specific BB like the FSA Platinum? Or just run one of those spec'd to work w/ both shell sizes? Is the spindle offset for E-type derailleurs? Thanx