I have been viewing this discussion since yesterday and have been hesitant to share my views, but I think since many people have been uncertain about the advantages offered by the "clutch cheat" I guess I would like to now share my views on the subject as well.
To see the effect of this cheat in action, look no further than the #1 ranked car at the current GTP Qualifier--the Mazda RX-7 at Fuji. If you watch that replay, look closely at the speed of the car along the main straight at Fuji. If the clutch offers a slight advantage over conventional shifting--and it does, just imagine the advantage that is gained when there is absolutely NO loss in acceleration when shifting. This is what you will see on the #1 replay at Fuji (in addition to obvious corner-cutting as well).
Others have said it may be worth up to a full second per lap, and I'm inclined to agree with that assessment. Obviously the size of the track and the amount of full-throttle/long straightaway sections varies from track to track, so the advantage would be smaller at a place like London--maybe only .4 or so per lap there, if that much. But still a significant advantage any way you look at it.
The RX-7 qualifier at Fuji is one of--if not--the most competitive TT's in all of Prologue. The #1 driver is fairly good, but he is nowhere near as capable as Timo, GTP_DHolland or MAY. I'm certain of that. Yet he is what, almost .3 faster than any of those drivers--ridiculous
I would guess that at this TT, the "clutch cheat" has given this guy close to a full second more than his talents could muster on their own.
I had the privilege of racing against FAK several times last week at 800 PP Suzuka, and I was simply amazed at his pace. In particular, I found it extremely difficult to even manage to stay in his tow on straightaways. For sure, he is definitely a better all-around driver than I am, and at my best, I could only hope to stay within .3 to .5 of his pace on most tracks. But I found it odd that he was getting such tremendous straightline speed at Suzuka, so much speed that I found it hard to stay in his tow. I just thought he must have been running extremely low downforce settings, but after reading Bruno's comments, if he was indeed flat-shifting, that would explain why it was so hard to keep pace with him.
This is really troubling to me
I really admire FAK and I think most people would agree he is one the very best out there, not only at TT's but in terms of racecraft especially. I'm not condemning him, just thought I would give you my perspective after racing him last week in the S2K at Suzuka.