Just to follow up, I spoke to someone at a local car shop that does customizations, and he said he wouldn't recommend taking off a factory installed lip spoiler to install a wing spoiler. He said that if it was bolted then you'd have to fill in the holes and paint over it, and if it was held down with adhesive then the underneath may not be painted because the spoiler may have been installed before the factory paint job. So either way (bolted or taped) it would involve a lot more than simply removing the lip spoiler and installing another one.