JBA headers advice?

okay i have a 06 2wd automatic 4.0 prerunner, and im running a single in dual out cherry bomb extreme muffler, the cats are all hollowed out, and dual 5" stainless diesel tips. I want to add jba headers to the setup but i want to know how much horsepower increase am i going to have. Any help?

 

the cats were hollowed when i bought the truck back in the summer, but i had everything else done myself. Its also got k&n intake and a Unichip programmer that was on it when i bought it, but i'm really confused as to why the truck is so powerful. I mean i was running 35"s when i bought it and roasted the tires with a power brake, but now i have 33"s and it burns out every time i take off from a stop. Dont get me wrong i love it haha, but i want answers to why its faster than a brand new ram with a hemi. Ive had it to 110 at most, but the acceleration is more than i would expect for what the truck is.

 

Damn i wouldn't have thought that would take power away from it. As far as the cats, i'm taking it soon to have the old cats just taken off, thats just a preference of mine because i'm in love with the sound of my truck, but with the intake what would you suggest to replace the k&n to add power? I'm sick of the thing anyway because lately the filter has been coming loose and rattling with an annoying sound. Btw i'm pretty sure the previous owner did re gear it for the bigger tires, but i'm not positive.

 

Thanks man i'll look into ordering the URD TCAI.

 

I just got mine installed a couple of days ago and im very pleased with them. Not to mention i got a great price on them (407 on autoanything.com, regular price 478 and i used coupon code "PBEB3" which took 15% off). I thought it was BS when people told me they were going to sound deeper but it actually did make a difference.

 

If previous owner regeared it then you just save alittle over 1,000$
As fot the headers, you lose low-end torque.
What i did on my tacoma was remove the rear cats since we have 4 of them. Its fast enough to beat v8's all day.
I also put a JET MAF which is a good add on. My truck had a slightly faster acceleration. Its for sale 100$ shipped if anyone is interested. Im putting a s/c so i dont need it.