Undecided on lenses?

[Milan Deo]

Hey guys so I've had my 600D with the twin lens kit for about a year and a half and I feel its time to upgrade to some better quality glass!!

So I mostly want to do rolling shots of cars during both the day and night, as well as your standard static shots and interior shots. So I was thinking of getting an ultra wide zoom lens as well as a standard zoom lens. I've got a rough budget of about $1100 Aud.

I would prefer one of the lenses to be at least F2.8 or even both. I've been looking at the Sigma 17-50mm F2.8 OS HSM and the Sigma 10-20mm F3.5 HSM how ever I've read that the Sigma 10-20 has some significant distortion at 10mm and also some cases of inconsistant sharpness? Would I be better off and wait a bit longer and getting the Tokina 11-16mm?