Gaining 40 HP is easy you may think. Just slap on a turbocharger or supercharger and you will gain much more than a measly 40 Horsepower. But then again any addition like this will definitely void your warranty and make you car illegal for highway use meaning you will never again pass smog. And if you get pulled over, you can bet a fix-it ticket is right around the corner. But with 5 simple bolt-on aftermarket performance parts you can net a 40 HP increase to your Infiniti G35 while keeping this ride naturally aspirated.
Starting with the Stillen Exhaust, this stainless steel unit improves exhaust flow for the Infiniti G35 and is considered a true dual unit. Also the exhaust has an X-pipe which keeps the flow consistent. A nice gain is noticed with 12 HP and 13 lb.-ft of torque being realized. The cost of this cat-back exhaust comes in at $1300.
No bolt on affair can be complete without an intake or air filter upgrade. The Stillen hi-flow intake kit totally replaces the stock aribox and consists of a K & N filter and housing. This is a great bargain at $195 and will net you over 5 HP. But there are even bigger gains throughout the powerband. This should be the first upgrade on everyone performance list.
Someone discovered that just adding an intake spacer to the Infiniti VQ35DE engine can give you some great gains. So again an intake spacer and plenum was added to this group of power enhancers. The MotorDyne 5/16ths spacer and MREV lower plenum cost $630, but they are a necessary addition if you want to reach that +40 HP mark. This unit provides a 10 HP bump, but midrange gains can be as high as 20 HP!
Rounding out the modifications is a set of Stillen Headers and hi-flow catalytic converters. These 4 parts complete the intake and exhaust modifications while adding an 8 and 10 HP increase respectively. The headers retail for $523 and the catalytic converters cost $500.
So for a mere $3159 you can have a sweet increase of 40 HP or a 17% increase in power for your Infiniti G35. And the best part is that if anything happens these parts are easily replaced with the factory pieces!