[KMPrenger]

Cold Air intake forsure.

Whether you do a cat-back versus an axle-back really is hardly any difference in gain...maybe a couple HP so as far as exhaust just go with whatever you like. Exhaust main benefit is sound and not performance.

The other big ticket item is installing long tube headers (which pretty much require a tune to stop the check engine light from appearing...the tune won't add much as far as performance though) or you can go with shorty headers. Shorties shouldn't cause a CEL if done right, will enhance your exhaust note, but only make about 1/2 to 2/3 the gain of LTs.

Only reason a tune might become absolutely necessary is if for some reason after all the mods your car begins to run an unhealthy Air/Fuel ratio which will hurt your power....a tune would bring that back in line.

Best estimate, with CAI, LTs, and exhaust I'd say your looking at a gain between 20 - 30 HP at peak. Should have slightly better gains lower in the RPM range.

OR if you have a manual you may want to consider skipping all of the above and just installing 3.73 rear end gears (which will give you as much or more TQ 'gain' as all of the above will) Of course it doesn't add more TQ, just makes the TQ your car already has much more useable. Then after that, determine if you'd still like to do a CAI or exhaust.