I think it would look fine. And for the speedo changes I think it is minimal.
Tire 1 Tire 2
Tire size
225/40-18 225/45-18
Section width 225 mm (8.9'') 225 mm (8.9'')
Sidewall 90 mm (3.5'') 101 mm (4'')
Tire diameter 637 mm (25.1'') 659 mm (25.9'')
22 mm (3.5%) taller.
Circumference 2000 mm (78.7'') 2069 mm (81.5'')
Revs per mile 804.6 777.7
When speedometer reads 60mph (96.6km/h) actual speed will be 62.1mph (100km/h): 3.5% faster.