FANS of Mercedes sports cars won't have long to wait for the latest version of the highly-prized SL roadster.

For first examples of the new greener and meaner version of the sought-after drop-top are due to arrive in the UK in a matter of weeks following confirmation of UK prices by Mercedes Benz.

But those lucky enough to be amongst the first in the queue for the sixth generation of one of the world's most iconic roadsters will have to shell out more for the privilege of owning the latest model.

For the "entry level" version of the new SL weighs in at the best part of £9,000 more than the cheapest version available in the previous SL line-up.

That's because there's no SL 300 this time round. Entry to the exclusive SL club now comes in the sleek form of the SL 350 and, at £72,495 on-the-road, it's even £4,000 dearer than its' direct equivalent in the outgoing range.

The SL 500, meanwhile, will cost around £1,700 more than the previous model at £83,445. Prices have yet to be announced for the SL 63 AMG and the SL 65 AMG which will become available later in the year.

Lighter, leaner, sportier and more efficient, the new SL is built almost entirely of aluminium and powered by Mercedes-Benz latest BlueDIRECT direct-injection engines which have improved fuel efficiency and push out 30 per cent less emissions than the previous model, while delivering even more performance.

The SL 350 is powered by a BlueDIRECT 3.5-litre V6 engine which is claimed to be 30 per cent more economical than before. Yet with 306 hp at 6,500 rpm and 370 Nm of torque at 3,500 - 5,250 rpm it also delivers sharper performance, accelerating the two-seater to 62 mph in 5.9 seconds and on to a 155 mph electronically limited top speed. This thrilling performance is complemented by excellent combined economy of 37.7mpg and CO emissions of 176 g/km.

Performance and economy figures for the SL 500 are equally impressive. The 4,663 cc, V8 engine - which combines direct injection and twin-turbo technologies - develops 435 hp at 5,250 rpm and an impressive 700 Nm of torque that is available from a low 1,800 rpm to 3,500 rpm. The 1,785 kg SL 500 will sprint to 62 mph in just 4.6 seconds and, like the SL 350, is electronically limited to 155 mph.

Even with the increase in power and torque over the outgoing model, the efficiency of the SL 500 has improved by 26 per cent, now returning 30.7 mpg on the combined cycle, while emitting 214 g/km of CO.

The SL's aluminium construction - a first for a Mercedes-Benz series production car - reduces weight by up to 140 kg, despite significant increases in safety and luxury features. The only non-aluminium body parts are the magnesium sections of the rear floor and the high-strength steel implants in the front windscreen pillars. The body is also significantly stiffer than that of the previous model.