If its still chilly outside, I would imagine the white smoke you are seeing has something to do with that. Have you tried smelling it to make sure it smells okay? like not sweet or acrid. ANd as long as you have no noticeable power loss, or milkshakey colour oil. I don't think it is your...
Personally I'd keep the 88 with the more reliable 22re. But really it all comes down to in the end is which one you enjoy having more. The 4 door or the Convertable.