You're putting weight at the worst possible place, so it will impact on your acceleration, your deceleration, and your handling. Whether you consider that a trade off worth having is up to the individual.
If you've already got heavy wheels on your car (OEM 18s or aftermarket ones, anything other than the Rays or the very expensive wheels basically) then you'd probably not going to lose out that much. If you've spent hundreds of pounds on intake, exhaust and remaps to make your car go quicker, it would seem a bit daft to then add weight back in to make it slower. Each to their own.