I've not had my Z3 for long but have enjoyed it so much I now want the few little extras you get with the 4 (mainly bigger boot for weekends away and proper window in the soft top). Question is which engine to go for. I have the 2.2 Z3 and would like similar sound and performance but an 05 plate 4 pot 2.0 Z4 can be had for the same money as an 03 plate 2.2 or 2.5 Z4. I would welcome any feedback from existing owners of Z4s before I take the plunge. Thanks, Deano.