Hmmm, this is what I was wondering as well... I know the N's have a nicely capped off end piece that is a little more complicated to modify.. Not sure about the S, C, F, or R model's though....
I think that the S and C would each be the same,
The R is like a N in most ways, except the exhaust
And the F is different as well.
Which model are we discussing here...?