Now when you say "increase the car performance" - yes it does. Electrical performance. Whether that translates into speed/torque/power I don't know. It really depends on the age of the car, how good is the ground, etc.
I recently installed a pair of adjustable cam-pulleys on my GSR. Everything ran like a charm till recently, on approx 30-50% of throttle once the rev reach 4000rpm's the needle...
I bought a wrong O2 sensor for my microtech ecu and apexi O2 monitor. Before that i use a unknown 1 wire O2 sensor from chop shop but it melt due to unknown reason. After that i change another O2 sensor...