Alright I can't decide which would be a better mod next. I already got an intake, and I got a RRM header on the way, but I don't know what to go with after that, a bored throttle body, or a catback exhaust? Anybody have any advice into this?

 

catback you get alittle performance increase but a great sound improvment. And the throttlebody is the same minus the sound.

 

Alright, does the throttle body make a more noticeable difference in the bottom end?

 

yeah, TB helps the low end (catback is for the high end) but if you follow the suggested upgrade patch, you should go something like intake > exhaust > TB andManifold > header > test pipe or high flow cat

 

Having done a lot, I'd rearrange Brians list to:
Intake- fast, cheap, simple. May actually show dyno losses because there's not a lot of places to put the extra air yet.
Header - feels good immediately. Mis range to top end. Shuldn't lose much low end
ported IM - again, good mod, helps with the low end and overall power. Seems to be good for making power at all ranges
Downpipe- you can really feel the throttle respose because the engine isn't fighting to push the exhaust through a crimped tube.
catback exhaust

Then cams > head > pistons ..... there's fuel management in there, bored fuel rail and.or rising rate FPR.... suspension.... good tires on light rims....
I'd actually advise against the test pipe, even with catback exhaust. IT stinks to high heaven and I noticed that it absolutely killed my low end.
I don't know about TB.... the IM opening matches the TB pretty well. Even when I port my IMs I don't like to take away too much material - I add about 2.5mm tot he diameter - so I'm not sure how much you'd benefit from a larger TB.

Other "freebies" include tightening the throttle cable and putting a hose connector between the two coolant hoses that flow into the TB (so now they flow into each other). This is to keepthe hot coolant away from the intake air charge. Maybe not worth a lot on the commute, but I'll take what I can get on the AX course. Also, you may want to keep the lines connected for winter, to help prevent freezing of the TB mechanisms.

Good luck!!

 

Catback will sound great.

 

Well I'm not really concerned about sound, more about performance. Are the gains actually noticeable with the throttle body or are they like the catback, some feel em, some don't?

 

yeah I got the greddy cat back from RRM .......sound...well it's not much sound at all actually, but I really like that. when I ride in my friends 240sx with his huge pipes it gets really annoying at 3500 rpms cruising on the highway screaming at the top of it's lungs. So if sound is what you are going for get something a little louder than the greddy full cat back system...just a heads up for those looking for a huge sound out of exhaust.

 

yea if your header is on the way, i would almost get both the throttle bodies and catback at the same time if you got the cash. that way you'd have the setup almost complete at once and would have everything working together in the car. the downpipe would help as well.
i have the magnaflow exhaust and love the sound. nice deep tone. i would def recommend it unless you're going turbo where u might want the bigger piping that the greddy offers to get the air out quicker.