A light that tells you if it's on or off? What happens when it works and makes a worrying noise? I can't see how a a cheap LED can diagnose a potential engine problem.

If you are hearing an ever so slight noise, it's fine. VTEC engages at 4400 and the secondaries at 5700, at which point you'll hear a whole new noise. In either case, just keep an ear out for a metal on metal noise and make sure you let it warm up before speeding around.

A two stage intake manifold allows air to enter the engine normally with your run-of-the-mill intended airflow meant to feed a regularly timed or variably timed engine. To increase performance, the ECU kicks open the additional intake butterflies (via a vacuum line) within the manifold to allow for the higher volume of air necessary to feed a high revving motor that has it's lift duration extended beyond the standard scope of a 1.8L engine.