honestly, neither is worth it. big tb's wont help you on a boosted application, the hp gain will be minimal at best. a better im is a better idea. and the i/c water spray is another worthless addition unless you're running a really undersized i/c. then having the cooling spray makes a difference. spend the $$ you would in the tb into tuning or a bigger fmic. for the cost of the nx kit, you can buy a HUGE fmic, along with paying for a very good tune (prices ive seen are around 500 bucks). imo most definitely NOT worth it for a mfgr's claimed 30 hp gain.