I plan on only buying performance mods for my '06 v6 that will increase mpg and/or hp. Is it worth the $300 or should I buy something else?

 

Yes, I would like to know also.

 

...NOPE. A throttle body won't do much unless you have a list of bolt-ons to combine it with or you are supercharged. Get an aftermarket tune on your car to start off with and then consider CAI, Exhaust, or Gears.

 

Aftermarket TB's are useless for power gains on a naturally aspirated 4.0 and 4.6L. If you want power, then go FI if you can afford it. If not, a CAI & custom tune will add about 15-20 RWHP on the 4.0.

 

I already have cai and dual exhaust. TB was next on my build list along with coil pack, plugs and 10mm wires and tune. F/I would probably be the last thing I do. Not sure what else I could do to increase hp without losing mpg's...

 

Aftermarket COPs do nothing unless you're FI and even then the gain is so-so. Try not to get blinded by the advertised HP gains. They're 99% unfounded.

A standalone CAI also provides minimal gains; on the order of 2-4 RWHP on the 4.0. These engines need a tune to make use of the additional air flow. Same for the duals; 0-minimal RWHP gain. Just tone improvement.

 

Soo what else can I do besides tune and F/I to gain hp without losing mpg?

 

The BBK will leave you stranded or throw codes at random.
Not worth the problems or the trunk storage space needed
to keep the OEM TB and the tools needed to replace it out
on that cold lonely road where the BBK decided to take a carp.

Put your $300 somewheres else

 

After the CAI & tune (and without FI or nitrous), your options are limited to minor gains. Gears will make you quicker but don't "add" RWHP. UDP's will reduce drivetrain loss to the tune of a few (3-6?) RWHP. A 1-piece aluminum DS will also reduce losses a bit, again to the tune of low single digit RWHP. I can't say what cams and headers on the 4.0 will do but on the 4.6 they provide good gains.

 

Preference on street tires?