it should be fine. right before all the crap with my car happened, i bought an X-Cal2. the tune on it included the longtubes. i didn't put it on before my car went down cause i didn't have the lt's installed yet. but once i get it back from Rick, i'll be loading that tune. then once the bottom end is broken in, i'll be going to DTP for a dyno tune...
btw, i don't know what kinds of headers you're going with, but if you're interested, i got the Mac non-ceramic coated and took them to Vanwin to get flame sprayed. i got the headers from AM when they had their big Mac blowout. i think i got them for like 250 or something, then the work at Vanwin ran me 175 i think. all in all, i paid less than i would have if i had gone with ceramics from the start. and Vanwin did a great job, and a pretty fast turn around, too...
