There are all sorts of good kits. Dr is arguably the best readily available 43mm, but there on others, 43mm Athena is pretty sweet too. You may have to build up the cases with some jb weld with either of these.
It depends on what sort of performance you want, rider weight, budget, and a number of other factors.
My go to set up is 46mm Pinasco, polini speed cases, aftermarket vario. Super easy, not as costly as other aftermarket cases. Works well with with my budget, weight, and my ideal moped performance. But there are a number of combinations of parts and ingenuity that could produce the same or better results.