I’ve had both. They give similar performance gains when you compare apples to apples and just run better octane fuel. The difference comes when you start modding you car more. The JB4 can be taken further with more
mods where the RC will not keep up.
I had an issue running the RaceChip fouling the plugs in a little under a year. This is due to they do not tie into the O2 sensors unlike JB4. Since RC does not tie into the O2 sensors with
fuel wires they have to guess and build fuel tables based on their testing. Obviously they are going to have to build in some fudge factor so they error on the side of being fat. If they errored on being lean well bad things start happening. The worst of erroring on being fat is a little worse gas mileage, or in my case, fouled plugs.
As far as installation is concerned they are both about the same. Three connection Ts for the RC and 2 main ones for the JB4 and then you can get Ts for the
fuel wires that make that pretty easy. If you get the
EWG wires that is pretty far down in the engine bay so if you plan on getting a cold air intake I’d do the
EWG and CAI at the same time.
The hardest part on installing these devices is not the actual device, but rather the
spark plugs. Get some swivels (3/8” and 1/4”), extensions, and a magnetic spark plug socket and it makes it doable without taking off the intake.