Sorry if I wasn't clear. I removed the wheels from the tandem because it's almost twice as long as a regular bike and would stick out way beyond the sides of the car. For regular single-person bikes it's no problem to leave the wheels on.
Like I said I've only used it for a couple of months and a couple dozen trips with bikes on it, but so far it's working great with no signs of paint damage or any undue stress on the spoiler.
This bike rack (and I'd assume any similar one that straps onto the car) is designed to fit many different cars, including full-size SUVs, so you'll have a lot of extra material in the straps once you get them sized right for a Spark. I use the extra from the strap to the bottom of the hatch to loop through the bike frame and tie onto the carrier to prevent the bike from swinging in and out in transit.
