Zooming through the hills I get a lot of understeer, so, obviously I would go with the rear sway bar. This raises the question: would I go with the thicker 19mm or the thinner 16mm?

I imagine the thicker would compliment better for handling if I went with all the chassis members, strut bars, etc. If I plan on buying the rest on a later date, which rear sway bar would you guys go with? 16mm or 19mm?

Cheers