I bought a 2003 2.5 for £4300 with 69k miles the only 3.0 models in the same price bracket had 120+k miles some quite a lot more or cat d cars . I am more than happy with the performance of the 2.5 I have a 2.8 z3 also and have owned a 330 ci so know what im missing but to be honest I didn't want to spend over £5k on a Sunday toy and find the 2.5 to be fine sure its not the fastest thing on the road but then again z4,s arnt exactly the best handling toys out there I think its a well matched package I am sure if your not expecting a super car then you will be more than happy with a lesser 2.5 