At a glance, between chart 'what I had' and chart 'what I'm going for', well, it looks like you'll be rowing more for the same effect. I'm not very sensitive so for me it's difficult to discern the difference between 138 mph and 140. But I can tell when I need 2nd to spin up to near 80, as opposed to needing to bang into the next gear another 10 mph sooner. Please note that I comment from the perspective of someone who uses my car almost exclusively on track.
I would also like to mention that, if you've got those nice steel rods sitting on a shelf w/ intent to install sometime, wouldn't you want to consider the effects of gearing at higher rpm values than shown?
I guess what I wondering is: If that VX makes big torque (we have no experience of them over here) then I kind of wonder why the change, at least as far as trackwork is concerned. If not trackwork, then, noting that the difference between the top gears of each is essentially non-existant, there won't be less engine buzz in top gear per 1000 rpm for the 6 speeder than the 5. So toodling down the motorway (or anywhere else) isn't going to significantly different, except for the quietness of the helical box of course.
Those Quaife numbers w/ the 3.95 look pretty good to me.
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Chris
Exempli Blatia