I am in the middle of writing something so no time to register. But my name is Dave and I live in GA. Mostly, I be writin' good

, but I have been mulling over a particular phrasing for the last few minutes. I think its just a style/preference issue. I tried to look it up on the net but that went nowhere as there are not good search terms, so I thought I'd post it here. Are there any rules, or preferences for:
I test drove several cars, of which two were quite hideous.
or
I test drove several cars, two of which were quite hideous.
??