Thats a rather big brush of tar you are wielding there Dave - I'm sure there are some out there that do No one I know of has tried a Stillen Gen3 on a 350z over here yet, bet that would make gains as they mess with the MAF housing diameter to confuse the fueling to compensate so the ECU cant dial it back as easy.
Always happy to help
Ok to be pedantic -
No CAI (currently fitted to any UK standard car) will add any useful or discernible increase in horsepower, although the noise made by said CAI will certainly add to the enjoyment of the driver and passers by.
* This statement is not intended to represent fact, merely the opinions of the poster *