I saw white wheels similar to those on a tC today and it looked great. As for other cheap mods, you could always tint windows/lights/possibly a lowering of sorts.
Avant Garde M310 18x8.5 Satin Silver. Downforce USA Front Lip. Engine Cover w/ Sonic Blue Accents. KW V1 Coilovers. OEM Titanium Headlights. OEM Replica Spoiler. K&N Air Filter.