Hm...Ok,not that significant,at least for the M.
Maybe that's the reason why George designed the M tip without 'em afterall.
Still this is my opinion ,mainly based upon my lungs capabilities and restrictions.
Moreover,if you ask me, I prefer the original M tip over the mod .
But I would also prefer a body w/o a carb .
Edit: I 've found though something that makes a difference ,
but not resistance-wise.
Preheating the M ,before the first main session (click to click).
Do a dry run first -if possible of course-after the cool down click load the M and then proceed further.
Makes a whole lotta difference !
Edit#2 : Black leather jackets and shiny steel.
Maybe too 80's .
Still holds the carb hermetically closed,
while making holding and rolling somewhat easier!
Cheers.