Looking good ben,it appears to be getting a bit serious in all departments.I assume you are using an A14 or 15.May i offer some advice we have learned from the race car? Depending on the ride height at the rear,be a bit carefull with using the H165 diff or bigger,you see to get power to the ground in these things you need to run VERY soft back springs,virtually stock as there is bugger all weight back there to transfer,which leads to the next problem,the big diffs hit the floor as does the tailshaft (13x7 wheels 60 series Toyo's) and when cornering at 10.5 tenths the rear axle housing has been known to hit the side rails(bump stops removed-no room)which can be a bit embarrasing if your not ready to catch it as you just ran out of suspension travel,so take some accurate measurments before you shell out any cash lowering the springs or buying diffs.Personally i would try a steel H145 first and see how it goes.Your right on the money with the gearbox,anything from the A series family is not worth stuffing around with,i have a shed full of busted ones.No advice on Watts linckage or Panhard rods as we don't feel the car needs one once you have replaced all the rubbers with nolathane or the like and get some half decent shocks on,rear sway bar,tried and removed,front sway bar in current service is Sunny wagon,seems about right,its attatched via a clamp arrangement on the tie bar next to the shock mount with rose joint link up to the sway bar,which has the tapered ends loped off,and it's the right shape believe it or not,it bolts to the side rails directly behind the bumper irons.I hope this has been of some use to you as we had to learn thru trial and error.Cheers