I have seen several cold air intake kits online.. Is it worth it to install one? How much horsepower am I able to actually gain??

 

If I understand correctly, the design of the stock intake is already a CAI design. The snorkel is taking air from near the grille area. I'd start with a JoeZ tube instead.

 

Not going to get much hp, just the noise all cold air kits make

 

SO if I wanted to make more horsepower what would be the first thing that I need to add to my IS?

 

a turbo/supercharger/new engine

 

Omega speaks the truth... even with full intake, exhaust, tuning, cams, whatnot, might be... MIGHT be able to get 200-210 wheel horsepower... stock is 170-180, in general... for what that costs, you could have turbo'ed the factory motor for a 300-350 whp, and if you spent a little more and built the bottom end, the sky is the limit power wise...

 

Interesting sounds like a turbo is the way to go then. This is really the first car I have ever tried to beef up so to speak. LOL I had a 02 Roush Mustang before this and the only extra I did to it was add a shot of nos to it.

 

yup mitsu is right. i did the whole intake, headers, exhaust deal with a decent tune and got 190/186 out of it. I'm building mine turbo currently ( still putting things together since I'm doing it myself ) and the expected power range from my GT45 Turbo is 330-380 @ around 10psi. stock internals except valve cover gasket and head gasket. got those a little thicker. but yeah if you get a good brand name turbo, and ebay exhaust manifold, down pipe and exhaust along with the oil lines, fuel pump, fuel regulator, and a decent stand alone you could spike the cars power up nicely. theres a lot of build threads you can refer to here to DIY or have an experienced mech do it.

 

FYI-
https://www.clublexus.com/forums/ls4...t-or-miss.html