Mercedes Benz CLK (C209) or SL 350 (R 230)?

Hy Community! I would like to buy a new but used Mercedes for myself. I would like to buy either a Clk (4 o. 6 cylinders) or a SL 350 (most probably from year 04) My big question is: Is an SL so much more expensive in maintenance (especially repair costs) than a comparable, or a slightly weaker CLK? According to my previous research, the differences in the costs of car tax and insurance are quite small (e.g. CLK 280: tax 202€, insurance 554€/year – SL 350 tax 256€, insurance 593€/year). And when it comes to consumption, the difference between two cars equipped with six cylinders should not actually be large either. So my final question: Why CLK drive if the SL is obviously not much more expensive? (loss of value and the benefits of a four-seater and a two-seater left out) Would I be very happy if one or the other might be able to help me with this big decision with his knowledge and experiences.