first of all those are REAL RACING HART C5's on his car not concept 5.
Second of all, you can tell how skinny those wheels look with a side view shot. you'd have to look from the rear. a wheel isn't just "an 18" or "a 17." u have to take into consideration the width of the wheel. for hondas and such stock wheel WIDTH is 7 inches by 15 or 16 or whatever. for sports cars like Zs they are usually 8 to 10 inches. generally upgrading wheels yous hould consider getting at LEAST 9's in the back (18x9 or 17x9). this allows u to run a 255-275 width tires. Concept 5 and "rice boy" wheels usually are at MOST 8 inches wide. this means you'll be running SMALLER wheels (width wise where it actually COUNTS for traction) and losing performance and making ur car look a LOT less mean and aggressive (steamrollers on the back of any car make it look powerful). i hope you understand this.