Anyone running wider tires/wheel setup? 295/40R20?

Been toying with changing out my 19" wheels for a set of 20's, seen a couple coupe owners that fit 285's, 295's even one said he was gonna stuff 305's on his Evoque.
Has anybody here go thru the trial and error process to see what fits and what doesn't?
I like the FAT tire look....

BUMP, I'm going to be switching to 20's soon and was wondering the same thing. The rims I have currently on my radar are a 20" x 8.5" so are 1/2" wider than stock, and I'd think I could go a bit wider than what comes on the stock RRE 20's??

Don't shoot me, but the X5 Sport with the wide/aggressive tires looks fantastic...ours look kind of whimpy next to them