You are close with the specs regarding how I lowered my car. It is a bit of a bumpy ride, but not as bad as you might think. However, I would suggest steel rims as I had bent the lip of one of the rims. (These are aluminum). MSR's It was something only I would notice and had to replace the rim. But, yes ruff roads are not your friend with this set up. I would suggest 18's instead. That way you can get a thicker tire on there and this will help a lot. P.S. I live in the country here in Northern California, You think your roads are crap??? It's friggin ridiculous here. HaHa Be Well and enjoy your HHR as I love my car plan to keep it forever.