Apparantly the Selespeed has a lower 1st gear so it puts less stress on the clutch during take-off. This theoretically should allow the car to accelerate quicker through 1st gear. The other thing that will effect 0-100km/hr times is the cars gearing ie. how fast will it go in 2nd. My 156 does about 60km in 1st and just over 100km in 2nd so it can get to 100km/hr without wasting time changing up to 3rd. I haven't checked the 147's gearing, maybe a 147 owner can enlighten me.
I have no idea how quick my 156 is to 100km/hr, I consider the 0-100km/hr figure to be a MIP (Meaningless Indication of Performance). Of far more importance (to me anyway) is the 80-120km/hr time.
There are so many factors affecting 0-100km times - road surface, how abusive you are on the clutch, mileage on the engine, tyres, weather etc. I read somewhere that these super quick low 4 sec times attained in the Mitsi Evo's are done by redlining the engine and side-stepping the clutch. You only get a couple of runs before the clutch is history. Thats one thing about the Selespeed - no matter how hard you try, you can't abuse the clutch during take-off.
Anyway, what's the big deal with a 0.2 sec difference in 0-100km times. My guess is that if all of us on this forum had a go at the 0-100km test in the same car there would be more variation in times than that.