What backspacing for billet specialties?

[SLPCobra]

Well im in the market for new rims since I damage one of them so it gives me an excuse to buy the rims ive been wanting lol

So the question is what backspacing would I need for my car?
I'm gonna be getting the 17x7 for the front and 17x11 for the back

It's a 1999 cobra with a 03 cobra irs

Any help is appreciated!

Thanks,
Zach