Jim
That would be right. When you calculate the mass of the cat relative to the weight of the bike + rider, the additional weight is negligible relative to the power output, and under normal roadgoing conditions, one would require a very accurate piece of measuring apparatus to see, within statistically valid tolerances, a "real" difference. So forget all the nonsense about the cat being "heavy". It makes little real difference.
However, even BMW agree that the Y piece allows a cleaner flowpath through the system and it is likely that when used with a performance exhaust + tuning "chips" and all the associated electromechanical gadgetry that so fascinates the average GSer, (even me !) that the net speed (based on most series of measurements) is undoubtedly likely (and I say, "likely" to be higher.
Also, the Y piece does sound "fruitier" as you say. It's a forlorn quest, really, as BMW fit cats because they're required by (their ?) legislation and because they quieten the engine, not surprising in a country where the Green Party was a leading influence on thought for so many years. Didn't they also develop the first recyclable car ?
I'd like to fit a Y piece but for reasons that are more emotive and red in tooth and claw than common sense alone. Logic should prevent us all from spending the money, but, hey, when we we lot ever logical ?? It's just not fun.
Toodle pip.
It was me keyboard honest
