Hi Dave,
Should have said, I have the 4900 saddle packs too - would have shown you.
The 3200 pack works very well (as you saw on Sunday
) & I was using less than 50% of the capacity per run, and fits the X-5 well, these will fit any car that has a 3+3 cell layout such as the Tamiya, BJ4, B44, Yokosmoko. The 4900 pack is taller, will require the battery posts to be spaced higher, there are other ways ofcause. The 4900 pack doesn't fit the X-5, as it will hit the layshaft.
The ideal for me, would be to heatshrinking the cells to the carbon battery brace, then mount the cells by the brace low - so that lays flat on the chassis. This becomes semi-permanent, and very secure.
As for the Aero and S2, it may be a struggle to make the 3200's saddles fit. I haven't looked though.
I was charging by the Trakpower charger with V-balancer, and I highly recommend it. Id choose this over a combined Nimh/Lipo charger, as there is no chance of screwing up. If you put Lipo pack on Nimh charge mode, they will be dead in the blink of an eye.
I will be at Southport again this weekend, anything you want to see just give me a shout. Can take my 3200's out of my X-5 to see how they fit your cars etc, and will have the 4900 saddle pack with me too.
Chris