Good memory!
Yep - i had these wheels on my previous zed and they were awful... they were so heavy that they ruined the handling of my car. I also couldnt get them balanced, i had a constant wobble above 80mph. The final nail in the coffin is that the metal rim is infact a very thin aluminium sheet - one day it just pinged up off the rim, looking like i had a buckled wheel, but it was just the ally sheet.
If i were you i would see if you can get some standard Rays wheels and feel how your car drives - see if it feels like a much better car (im sure it will).
RE spacers, these wont affect your handling at all and they're perfectly safe - but they will make your car look a lot cooler