hyundai make one, comes painted its side skirts, front and rear lips
then you can put the optional rear wing on it would cost around $1800~$2000 all up BUT you know it will go straight on, require no "panel/prep work" and no painting...
almost all fiberglass body kits require work at the panel shop to make them fit and it can be quite costly!
i plan on getting it (genuine one) at some stage
there are a few sites that do body kits, just do a search on here mate infact there was one or two mentioned on here just yesterday!!! ebay is also a good place to look!