First you have to ask yourself if you really need the adjustability of coilovers. If not, you're probably better off with a set of progressive rate lowering springs and a nice set of shocks.

If you do need the height adjustment, I would recommend a "full" coilover setup. I've heard too many bad stories with the "sleeve" coilover setup (I have one myself) and am seriously considering a "full" coilover system.