oo7ml said:
1 - the 2008 Z4 Coupe is a year newer (matters more in Ireland i think than the UK)
2 - the 2008 Z4 Coupe has a much better fuel consumption
3 - the 2008 Z4 Coupe has less mileage
4 - the 2008 Z4 Coupe is slightly cheaper to service
5 - road tax is €600 cheaper a year on the 2008 Z4 Coupe
My view, from afar:
1 - Year: Both cars are not the current shape E89, so one year older or newer will not make any difference, unless you plan to sell it again soon.
2 - Fuel consumption: On the commute mileage you mention the difference in fuel consumption is immaterial - even at your high fuel prices.
3 - Mileage: Be careful on this one - very low mileage may indicate a car that stood for long periods without being driven, which IMHO is much worse than a higher mileage incurred over regular trips.
4 - Service costs: I know that your labour rates are much higher than ours, but the Z only gets serviced roughly every 12000 miles, so the difference is once again immaterial. Change the oil yourself in between "official" services.
5 - Road Tax: This aspect is absolutely outrageous - I believe you and your countrymen would be justified in taking up arms against your government. My annual "road tax" on the Z totals roughly €36.
6 - The number of owners: This would bother me a little bit, but to really evaluate this you would need to have spent time as passenger with each previous owner. Did any of them routinely use the "clutch slip when stopped at red light on incline" method? Or the "rev it higher when cold so it can get warmer quicker"? If you don't know and cannot find out, ignore this aspect.
In your shoes I would focus on only
one thing: which car will best suit your personality/driving style and the road surfaces you typically drive on. The M is a very harsh ride and can be tiring on irregular tar - my wife hates it. On the other hand, the M is the best toy I have ever had - it begs to be driven enthusiastically. If you are Dr Jekyll/Mr Hyde, get the M. If you are always Mr Equanimity, get the 2008. Drive both before you decide.