=== 1 WEEK LATER - THE RESULT ===
I bought my SX3, wired it up and raced for the first time last night.
This was the very first time I had run the car so didnt know what to expect.
All I can say is Wow!
I was expecting it to be very similar to the SX2 with maybe a slight change in balance and stability, but it really was like a completely different car.
The steering response is fantastic, and Im not sure why, but its way better coming out of corners under power - I was able to keep more power on for longer, and this resulted in better lap times.
That said, my speed round the track didnt go up by a vast amount, I think I was probably just about as quick, but whereas the SX2 always felt like it was on the edge, the SX3 was definately easier to drive well.
Because of this I needed marshalled less, and ended up getting my best ever result!
The added bonus is that with some setup and some more practise, I know I can do better.
Thanks to everyone who helped with great advice and tips.