The 2.0-litre petrol engine powers the entry-level Z4 sDrive18i, which also powers the sDrive28i. Delivering up to 154bhp, it’s got enough in its armour to get you from rest to 62mph in just under 8.0 seconds before maxing out at 131mph. Not exactly the quickest, and it also feels breathless up hills.
A 181bhp variant is much quicker, and does the 0-62 dash in 6.9 seconds before topping out at 146mph. For more pace, the 242bhp is an option – it blends performance with decent economy and can gun you from a standstill in 5.7 seconds.
A large 3.0-litre petrol engine delivers 302bhp and does the same distance in 5.2 seconds, while the sDrive35is rounds off the range, doing 0-62 in 4.8 seconds.
Without a diesel engine in the range, fuel economy is not as good as it could have been. You won’t have to pay through the nose, though – the BMW Z4 Roadster is cheaper to buy than the Porsche and offers reasonable economy. The cheapest engine to run is the base-level 2.0-litre, which can achieve average returns of 41.5mpg while costing £185 a year in road tax.
The BMW Z4 is strictly a two-seater. It’s reasonably practical, and comes with a good amount of standard kit. Inside, the cabin feels special – the materials are top quality and durable, while the brand’s iDrive wheel is, as always, a highlight. It controls the infotainment system, sat nav among other things.
The Boxster is more practical on the whole. Whereas its roof can be tucked away in less than 10 seconds, the BMW’s takes over 20. And when you do put it down, you lose a considerable amount of boot space – it drops from 310-litres to 130. There re just two seats, but they should offer enough comfort and space to the driver and passenger.
BMW – £29,700 – £48,000