new mounts went in rear and front (75 mounts, base plates removed) examined centre bearing, front donut , all great. marked everything up (even though I dont believe the nut and bolt myth, all bolts in mine are all the same).
Anyway put it all back together, left front pinch bolt undone and started her up ran for a few minutes, allowed to warm up, then revved a few times still jacked. Huge difference straight away, she revs right the way to red line smooth as silk. One weird thing though, vibration at 1200 rpm, nothing at 1000rpm, and yet dissapers at 1300 and smooth all the way to red line.
weird!! anyone else had that? Im stumped, pretty odd that the correct mounts and new rear donut have eliminated vibration through out the rev range apart from 1200rpm? front donut and centre bearings/donut were perfect. hopefully wont even notice it whilst driving it, not at 1200rpm very long..ever 
Anyway, goes to show the extra few mm on the forward mounts can cause vibration on the gtv6
I guess this was the "vibration" at high speeds (190-200km/h) As you can see I'm missing the rubber part of the bump stop. I've made a new one. Now with rubber tip, it protrudes 3cm above the floorpan. Is it enough, or should i add let's say one cm more?
, rear guibo should never hit the floorpan at any speed or acceleration, maybe your missing snubber was allowing it too ride up too far, but the front box mounts shouldn't allow that much movement. the tranny shouldn't be touching the snubber for any more than a moment under hard acceleration anyway. the gap between top of tranny and snubber on my car, after correct front mounts is no more than a 2mm static. are you sure you have the correct rear guibo installed, and gtv6 mounts, rather than Milano/75 mounts? post a picture of the whole rear guibo and tranny spider area if you can, lets have a look.