20s are too big. Even if they are "light", they are still too big. You will have another inch of rim to fit under your Fenders
, but your tires can't get any smaller. 35 and 30 are already postievely minimal, any smaller and those new wheels will be all bent out of shape (pun intended) very, very quickly. It's hard to believe that you can even drive uphill anymore, 19x9.5?
That's like 350Z Turbo size, not FWD, no torque Celica.