ok 2007 883 low ... i have drag pipes on it now had the 1200 conversion done doing alot of backfiring after i release the throttle,,,i want to change the pipes but i want pipes the have the o2 sensor ports,, but want pipes without the cross over tube holes on the bottom want to do away with cross over tube any suggestions on a good deep sounding pipe with o2 holes but no cross over tube holes ?