Monsieur Bonjour 
2003 BMW Z4 Convertible 2.5i 2dr Roadster (2.5L 6cyl 5M)
Better than the 3.0
 I'v tried the 3.0l and I didn't see a big difference in the power for the 10000$ you need to add to get the 3.0 compare to the 2.5. The 2.5 is more than enought with the sport package. I had some problem with the radio & amplifier and the automatic roof top after the BOOMERANG DEVICE installation be careful there is a lot of sensor on this car everywhere. Fun to drive and everybody think it's worth twice the price you pay... If you want to flash in a sport car it's the best one to buy but more than  everything else it's fun to drive. You can't not resist its race feeling. You will step on the gas after every stop sign. Enjoy 