Thanks for the suggestion, I'll look into it.
I have come to the conclusion that it is better to buy the components separately as you suggested. However, one kit has caught my attention today and an unboxing reviewer was impressed by the quality of the components, particularly the lighting system which is very unique.
It is the Eheim Aquastyle 35 liter, a German company and available here in Switzerland.
https://goo.gl/Oy6IFh. I think it is time that I paid a visit to my local aquarium dealer and see what he says. Again, thanks for responding.