Well I pulled the trigger on the Hooker crossmember to see how it fits with non hooker mounts. I am using 1" offset mounts from car shop Inc and poly inserts in my factory clamshells and a poly trans mount. My swap is a LS with a th400 and it seems that everything lined up perfectly. The exhaust they sell for the complete swap is 2.5" but I believe that there is enough room for 3". I am also running the budget swap headers from hawks.