Hey mate, its my pleasure to help
Now with your new gearing, i would reccomend you put your first spur gear down to a 60 tooth as there is quite a big jump between 1st and 2nd.
Trust me on this one, the GXR motors do rev out quite hard and aggressive but they keep on going, try to keep your temperature within 100 to 130 degrees celsius.You seem to be running quite soft tyres, on cold days i run 35's all round, but just for normal temperature days, i used a black Kyosho pipe, or a JPL workes pretty well, i found the jpl restricts the motor a bit but the kyosho lets it rev free. I like to use a mid range tyre like a 37 shore..on my SIII i didnt get much tyre wear at all so i ran 37's in 1/2 hour finals and had better grip than everyone else. Now down to droop. I like my car sensetive and responsive so i tend to put lots of droop in, around 3-4mm on the front and about 5-6mm on the rear, i know it is a lot but it just makes the car heaps more responsive to commands, this droop setting alters to different tracks i race on. When it comes to shock oil and springs i run 45 wt all round with kit black springs. In the rear diff i use 30,000 wt with 4 spider gears, and a locker in the front.
its hard to tell you what camber to run coz i dont know what your track is like but try about -2 degrees on front and about -4 on rear. With Caster i run it in the kit position. No, i had on motor that wasnt hitting..these engines are massed produced, its just a case of if you get a good one or a bad one, they are all different. For fuel i run Sidewinder 16 % nitro and 11% oil.
With your 2 speed, the standard 2-speed clutch springs are really soft, so you need to crank them all the way in, they are also really un-consistant, so i got either mugen MTX 4 or Kyosho V-one-RRR springs and it fixed it immediately, i hope this is of help to you, feel free to post something on this forum or just drop me a p.m, cheers guys