All,
Don't spend your money on titanium etc. It will not be any faster anyway. With these Gt-cars it's all about the handling of the car, smoothness of the clutch and driving.
First, if your driving is not constant, (say every lap inside same 0.5sec and usually more qualifiers without mistakes than qualifiers with mistakes..) focus on the driving and working with the setup. Spend the extra money to the fuel, tires and engines. It gives the better pay-back for the money.
If you still want to go for the lighter car, the best solution is the brains and the dremel, not the money and titanium.
Waste the windows of the body, waste the rear bumper and the diffuser, shorten the body-posts. change the cooling head to 1/8 onroad cooling head. Change the rear upper arms to normal buggy type ones (gives more tracktion also). Dremel the plastics!! thats the heavy part, not the metal. And use LiPo for the receiver.
That was the recipe for me to win the nationals last summer..
-X-