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One Lap of the Web: Elon Musk's Hyperloop, Greenwich Concours and a Model T

We spend a lot of time on the Internet -- pretty much whenever we're not driving, writing about or working on cars. Since there's more out there than we'd ever be able to cover, here's our daily digest of car stuff on the Web you may not otherwise have heard about. The 2013 Porsche Rennsport Australia went off over Memorial Day weekend at Sydney Motorsports Park and motorsportretro.com has full gallery of pictures.

New Mercedes SL 400 replaces SL 350

The new Mercedes SL 400 (pictured) replaces the old SL 350 It’s a little over two years since the latest Mercedes SL arrived, and Mercedes has now decided to add a little zest to sales by dropping the old SL 350 and replacing it with a new Mercedes SL 400. The new SL 400 gets its power from the new E400 which means a twin-turbo 3.0 litre V6 with 328bhp and 354 lb/ft of torque – 26bhp and 81 lb/ft more than the old SL 350 – enough to let the SL 400 scoot to 62 mph in 5.2 seconds – 0.7s better than the 350 -= and on to a limited top speed of 155 mph. The new SL 400 has to make do with Mercedes tried and tested 7-speed auto – despite a new 9-speed now being available in Mercedes’ arsenal – which gives the SL 400 official economy of 38.6 mpg and emissions of 172g/km – not that you’ll come close in the real world.

Infiniti: M can be about mpg or zip

Infiniti will face a new marketing challenge when it introduces its first hybrid vehicle next spring, the 2012 M35h sedan. Since the import brand has never sold a hybrid, officials will be attempting to learn which marketing chord resonates more with its customers: performance or fuel economy. "The marketing will center on the point that hybrids have always been about compromise," says Ben Poore, Infiniti Business Unit vice president.