Is the 7D worth it?

[98kellrs]

Well it's tax time and I'm looking to get some new gear with my rebate. I'm budgeting around $2000 for gear, software, cards etc and I am tossing up whether it is worth upgrading from my 600D to the 7D.

I mainly shoot motorsport and sport so the 8fps would come in real handy, but at the same time (I think) my 600D has the same 18mpx CMOS sensor, and Digic 4 processor as the 7D. My photos through the Sigma and nifty fifty lenses are coming out great, nice and sharp with very little missed details. Besides the extra fps, more AF points, and build quality are there any features of the 7D which would make it worth upgrading to?

My other option is to upgrade my standard zoom kit lens to a EF 24-70mm f/2.8L USM which would cost a fraction less than the 7D and would be a massive step up from the kit lenses (18-55mm & 55-250mm) I currently use in terms of IQ.

Any advice would be greatly appriciated!