Ya its crazy eh, thats 79mph on the Road Angel plus so 85mph on the clock. Its a great gear as it only drops 1.5k from 4th to 5th, but equally frustrating for its vtec engage point on the motorway. I find I drive much more calmly & sensibly with it which is a good thing.
Positive notes on the gears so far, acceleration of course, charging up through the gears is awsome, but also when you take your foot off the go pedal it slows down much quicker, handy for gatsos & fast driving. Steep hills in a lower gear and the car doesnt really speed up so it doesnt 'get away'.
Downside is cruising in 5th that I have mentioned but also it is noisy, 75mph feels & sounds like 95mph. I think that with this gearset if you had upgraded to a 4.78FD it would just be way too noisy (especially with an aftermarket exhaust). Petrol consumption is also up, over 70mph (gps) it increases slightly, then nearer the 79mph (gps) you can really notice it, Therefore if you do a lot of motorway then stick with the 1.000 5th.
I think whatever tuning you do to your car mpg will suffer so its a sacrifice.