Congrats Steve. I got mine done by one of Simon's agents here in NI on Tuesday past.
I too find the car more powerful without loosing the smoothness. It now has serious kick-in-the-back when you floor it.
Like you, I find the traction control light coming on sometimes, but it does not seem to kill the power as much as it did in my E46. I suppose it is just a more advanced system. God help the RFT's
The only minor niggle I can find so far is that sometimes when moving in slow traffic (5-10mph) with low revs, the auto gear change is slightly more 'shunty' - perhaps because of the extra torque ???