My car is a '13 and not a '14, but I will give you my input.
I get on other message boards and the guys are paying fortunes for F-Sport parts to upgrade their cars. I think my F-Sport option was $2400. WELL WORTH IT! I love my rims, my car sits a little lower, great front end and grill, badges, aluminum pedals, steering wheel. Now I added the shifter knob too. I think it just totally takes the car from normal to very sporty. I would not buy a Lexus that didn't have the F-Sport package.
I don't know the particulars of the suspension, but my car corners great. It rides a little rough, but I don't care!