I don't think you will get more go. You will gain about 5000 pounds so if there is a power advantage to the Series 60 / World transmission combination it is to a great extent offset by the weight.

The 8V92 / 5 speed combination drives different than the Series 60 / 6 speed. Because the 8V92 is a rev happy engine it really doesn't come into its own until your get around 1500 RPM and can peg the turbo boost. Then, because the 5 speed will hang in each gear until the engine hits about 2100 it is in its element. You do tend to drive that coach with your foot on the floor. I guess the saying is drive it like you stole it.

The Series 60 / 6 speed combination takes advantage of its low end torque and is set up to be biased towards economy. Coming from a stop, unlike the 8V92 you feel a push in your back due to the low end torque. But unless you always run in performance mode, or manually shift gears the transmission will short shift and shift at relatively low RPM. It will also delay the downshift, being set up to lug a bit before it drops a gear. Obviously you can squeeze better performance by selecting the preformance mode which will encouirage quicker downshifts and will hang in gear longer, but the shifts will be harsher and econmy will suffer.

I'm OK with the set up as it is and drive in economy mode most of the time. In mountainous terrain I may either leave it in 5th manually, letting that be the high gear instead of 6th, or I will select the performance mode. Either way I can get better hill climbing performance than in economy. Generally unless the mountain or upgrade one of a continuous series of them I hit the bottom of the hill in 5th and accelerating with the transmission in performance. But other than that I don't mess with it very much preferring the almost undetectible upshifts. I particularly like the fact the transmission does not hunt, something the 5 speed would do.

I think is a drag race both our coaches would run side by side if the race started with you having some revs, such as in a rolling start because I think that is the only real diference.