^ The issue is what size spare to put in... if you put in a 17" spare and get an 18" flat you're screwed and vise versa.

Personally I have all 18's so I could do it. Just get the newest generation run-flats or get a tire-inflator kit like my Z06 comes with. Oh and having AAA and a credit card can come in handy for road trips.

FWIW the "tub" in the rear of the C5 was actually designed to house a donut spare as during the design of the C5 platform runflat technology was new and had not been given the go ahead... hence the curvey catback exhaust vs. straight out.