With practise I don't even think there would be a significant advantage in the upshifts for clutch users
I'm already managing very fast and clean shifts with no noticable clutch heat on my momo two pedal setup.So racing with a clutch pedal is a disadvantage all around still
but your right it would be much more fun and because of that I am having a very hard time restraining myself from rushing out and buying an G25
or alternatively building my own pedal setup 
@ pwrslave - I thought that also. For me it's actually been the opposite, I've actually been reluctant to push LFS as a true simulator up until now. While the physics felt good I didn't really feel it was or could be classified as a simulator
but now that has changed quite abit and I can feel comforatble to push LFS as a simulator on PC to those that drive as a passion in real life 
We should drive like in RL, and if in RL every racing prepped car, club or pro series have that auto cut off thing, than we should have it also...


. The full manual with a button mapped to a key is a bit tricky to master but with practice would be quickest (but i won't be using it unless i grow another thumb overnight, or figure out a way to build one into the gearstick) And the auto clutch is about the right balance and really immersive. Ok so the throttle blip mid change is out the window, but i can live with that ( i'm never gonna be quick anyway so who cares)