On small indoor tracks I have seen the Tekin and the SPX go good.
The GM I don't now.
But the best thing is. more and more GM and SPX drivers switch here to Tekin.
Well that's in Eindhoven... Not the whole Netherlands ^o)....
A club member was asking me what to do with the space he has over now he has a Tekin.
It's the smallest from the 3. He was surprised that it was so small.
By the way, how many come from the Netherlands in this topic?
Because I think that the Americans don't use the GM as much as we do in Europe.
We are here to take over the world!!!!! Moewhahah 
When I get my photon I hope now finally to have a lighter car.
I have also shortened the wire on my servo. With the light Tekin it must be possible to stay close to the 1400Gram.
My TC5R (not the newest car) is just with already 30 grams of lead just below the 1400.... hoe heavy is that tekin ;-)