DTLT's are worth atleast .25 in the 1/4 mile over stock manifolds with cats in them. Some guys gain .3-.35 with them with the right exhaust set-up.
I can tell you this, danblp/Ben ran hit doug thorley's for a long time and ran countless 1/4 mile times on his Gtech pro unit. He recently switched to Nismos and gained .08 in the 1/4 mile with them and everyone knows that Nismos are the best header with most gains for the T. My point is, if he only gained .08 with them then the DTLT's are obviously worth at least .25 in the 1/4 mile for someone going from stock manifolds with cats in them to LT's.We need some stillen and doug thorley owners to post their times so we can get some comparisons,
It would help me decide which one to get since I will be getting longtubes August or September.