I posted on the V10 forum about this problem I experience on my 05 E-Gear.
I think we are expriencing the exact same problem. The lag only occurs from 1st to 2nd when pushed hard on Sport Mode.

I am going to have the car looked at by Symbolic and may need a re-flash of the computer.

If you already had the problem corrected, please let me know what they did to correct it?

Thanks