If you're moving to wider tires I would do the brake upgrades sooner rather than later. ESPECIALLY if you decide to go 18x11. And don't forget brake cooling ducts.
Oh, and the 18x11s may need caster/camber plates to keep them tucked in under the fenders.
So got word back from SCCA, since I upgraded 2 and not just 1 of my sway bars, I am no longer able to stay in STOCK.... <shrug>, price was right, and I can already tell how much of a difference they make. However, they accentuate my 17" rims / sidewall issue. And those could only go up to 9inch wide (+1" over stock)in the stock class. So 18s (10 vs 11 tbd) but I'd like to have street tires that are a little more all season vs track tires, we still get cold and snow in CO till April and I plan on driving this thing almost year round. Looks like castor plates make sense for the next update with rims.. It never ends.