This is where I have to say I'm rather ignorant - sadly not the first time thats been said .

Should I be replacing plugs based on mileage covered, or should I take 'em out and inspect for some sign that they need replacing, or will the engine starting / performance tell me when ???

My bike is stock '96 MC28SP, except for M Max race pipes. Not sure of the airbox has been modified / drilled - I keep meaning to check but haven't got the tank off yet so don't know. Would I be best off with the standard BRM9ECM and 10.

What would the "shorty" HRC plugs do for me?