I disagree that a cheap kit is the same as a Jap brand or plazmaman kit.
I recently purchased a Plazmaman piping kit for our Project car and was very happy with their seamless aluminium mandrel bent pipes.
At the end of the day its about cooling efficiency with no pressure drop and some do it better than others. Not to mention removing as many restrictions from the system as possible.
The reason you pay more money is not just the label, but the R&D that goes into different set-ups.
For reference I use a GReddy core and Plazmaman piping. I have no affiliations with either company, only personal preference.