just to echo what brian 4 said,
don't wait till summer , mine is my year round ride and has done 14k since purchase in may..these little cars are bullet proof,and are fun to drive in almost all conditions...the only issues I have had are windscreen washer pump,(replaced for £6 on ebay) and the power hood microswitch which I replaced with one from maplins at the grand cost of £3...per a fantastic wiki article on this very forum,
with the yearly service including consumables at my local indy costing £195 inc VAT, so far servicing wise per mile, this car has been cheaper to run than my vespa GTV 250,which cost nearly £300 on the last time it was done..
purchasing a Z3 was one of the best decisions I have ever made car wise and it rates so highly on the smile-ometer it's ridiculous, so much fun for so little money