PLUS Performance Package install on Long Island

Hello,
I found a site that sells the components (springs, sway bar, ground effects, wheels) of the PLUS Performance Package for decent price, I'm now looking for a place to get them installed on my 2013 Prius Two. I live on Long Island (Nassau), anyone know of a good place to get them installed? I understand dealers may have Toyota trained techs who should know the Prius, but how would I know if I'm being charged a fair labor cost?

Thanks.