My rear has .15 Toe. Now is that really bad to the point where I shouldn't drive it? I think the Max specs for our cars is .10.

 

I take it that's toe in? what is 0.15?‹ in inches or mm?

 

You don't say what size wheels you have. The specs are different.

Tow range for 18's is .043 - .106 with nominal being .075 (these are inch measurements). Your .15 will cause increased wear across the whole tire.

Sure you can still drive it but if you want to save on tire wear you should have it aligned.