You should be fine with those specs & rear 12mm spacers. I'll be using those exact specs in the front as well but with a different wheel. IMHO, I wouldn't run spacers but that's just my paranoid self talking. However, I read somewhere recently Breyton's going to make a better fitment for the rears without spacers but not sure if it'll be soon or not. I suggest contacting them directly to find out.
I'm not a big fan of BBS due to the fact they're overpriced! Don't get me wrong, I love how the LM-R's look but they're not worth the $$$ asking price as fine of a wheel they are. Plus everyone & their mom, sister, dad, aunt, uncle, cousin, nephew & niece has a set of BBS wheels.
And that includes me in the past (before their ridiculous price jump).