Between SLK and MX5, the MX5 is easier to maintain, for sure.Hi Ism1991, thanks for your elaboration.
I personally do not like BMW Z4, because of the head of Z4 too long and rear too short, sort of imbalance.
SLK seems like a good choice, between MX5 & SLK.
S2000 seems like very old already
If you're willing to look at the SLK, then you should consider the Porsche
BUT, if reliable, easy to maintain, MX5 for sure over the continentals.