ah yeah, I see where you are coming from. no the move is inspired mostly by my desire to run one brand for the season (summer here) as I run e buggy, nitro buggy and nitro truggy, of which I already own the Xray truggy and XB8 (yet to run) as buying spares for 3 different brands was a PITA lol

The Tekno was definitely an eye opener as regards steering and stays near the top of my list of brands to run again in the future. I lust after the truggy!

per your other points, yes i tried weights near the rear bulkhead and that worked too, (would be similar to running the engine in rear position) but with my driving i preferred it on the hubs, plus it needed more weight in that position than on the hub for the same result, and steering was not affected as much running the weight on the hub.
But yes, if the car starts getting out of shape, extra mass will affect the dynamics, although we are only talking 10+10gram here (same as some mud sticking to the inside of my wheels)