In my case, I've had great support from the people at Zenith. They answer the phone, respond to emails, and give so much support, I did not begrudge the $345 (I think it was) for the upgrade kit.
They provide four levels of kits -- scratch built (plans only), regular kit, quick-build kit, and RTF (but not from the Mexico plant.) In my case I bought the regular kit a section at a time -- rudder, tail, fuseledge, wings, fuel system, landing gear, etc. I could buy the regular kit a section at a time when I was ready for it, and that spread the cost over three years.