OMG did you really put this shitty tyres on Z, what is the point to save few quid and have bad tyres on car...
If you wanna save few quid on tyres buy Maxxis VS5 or Sava UHP2
Maxxis have stiffer sidewalls and feels more sporty tyre, both have very good dry grip, and are good on wet, Sava will last long time as is known for Goodyear tyres
For best dry and wet grip buy latest Pirelli P Zero, but will not last as Goodyear or Michelin, for someone with low mileage is a best choice
As for wheels I have weighted original 18" wheels and are very light at 11.5 kg and strong, what you cant say about aftermark wheels, for me 18 " are best design after R wheels, light wheels are way to go if you wanna great feel when driving, 18-19" wheels will make no difference for road holding, but tyres will make a big difference
Cheers