After some thought and using their Analyzer, I have decided to go with the TK0-600 (0.82).
You're right Robb, that 5th gear drop with either the .64 and .68 is far too much IMO.
The following is for those how maybe looking at getting one, just a little chart as an example.
My 'Cuda: 275/60/15's & 3.23 gears this is what I would be driving like:
TKO-500 (0.68)3.23s = 3.98 1st gear ratio.
65mph in 5th is 1700rpm.
A lowly 2,300rpm is 83mph. lol
TKO-600 (0.64)3.23s = 3.49 1st gear ratio.
65mph in 5th is an idle like 1,600rpms!
A lowly 2,300rpm would be cruising at 93mph.
TKO-600 (0.82)3.23s = 3.49 1st gear ratio (spot on for my 340 combo, perfect launch, same as the .64).
65mph in 5th = 2,100rpm Much better.
2,300rpms is better throttle responsive 72mph.
So I can see what you're saying, having the TKO-500 would shred the tires and be very short in 1st and going into 5th would be almost a waste, driving wise. I just don't want to go into 5th gear corners basically at idle. lol
I'll just double check that the 'Cuda has indeed got 3.23:1 gears as I'm only going off what the previous owner told me. If they're not I'll look at something very similar rpm wise for the gears I have. They are so quiet and smooth (the gears I have now) so I don't want to go looking for new whiny ones again.
Cheers,
Carl