You do have some things right..less rotational mass with 35 series tires however the smaller the diameter the more revs go up at a given rpm. Remember gxp has a overall 2.93 gear ratio. Handling would be nice but your car would look uber gay with all that gap without lowering the **** out it.you're also going to throw off the abs so you'll need a tuner to change your tire height in your pcm.