The updated BMW i8 hybrid sportscar will arrive in Aussie showrooms later this month, debuting a new Roadster convertible that will top the range at $348,900 before on-road costs.

In Coupe form, however, the plug-in hybrid checks in at $318,900, which is $30,000 cheaper than the Roadster, but $15,600 more expensive than its predecessor.

The all-new drop-top uses a power-folding fabric roof that can be operated at speeds up to 50km/h. It also features power seats with memory, and in-car storage compartments front and rear.

Other interior equipment includes a 10.21-inch iDrive infotainment system with voice control, digital radio, USB connectivity and an 11-speaker Harman/Kardon sound system.

Interior equipment includes a 10.21-inch iDrive infotainment system with voice control, digital radio and USB connectivity.

For lighting, the i8 employs LED adaptive headlights, daytime runners, tail-lights and reading lights.

Sticking the car to the road is a set of 20-inch alloy wheels that are wrapped in 195/50 shoes at the front and 215/45 at the rear.

The i8 employs LED adaptive headlights and daytime runners.

As already reported, BMW has tweaked the i8's electric powertrain, getting an extra 9kW to the front wheels for a total 105kW and 250Nm.

The rear wheels remain driven by a 170kW/320Nm 1.5-litre turbocharged three-cylinder petrol engine mated with a six-speed automatic transmission.

Working together, the BMW i8 is capable of producing 275kW of power and 570Nm of torque.

At full tilt, the i8 Coupe will accelerate from zero to 100km/h in 4.4 seconds, while the rag-top Roadster will do the sprint in 4.6 seconds, 0.2s slower.

BMW Group Australia chief executive officer Marc Werner said the addition of the convertible will help boost the i8's popularity.

“The BMW i8 hybrid sportscar has justifiably served as a futuristic halo for the BMW brand since its 2014 introduction,” he said.

“With the latest updates, including the debut of the incredible i8 Roadster, BMW i is again trailblazing. With increased power and storage capacity, it’s the best of both worlds.

“The BMW i8 Roadster delivers the open sports car experience with zero-emission capability, and it looks truly stunning.”

2018 BMW i8 list pricing

BMW i8 Coupe – automatic – $318,900
BMW i8 Roadster – automatic – $348,900

BMW's new i8 Roadster brings open-top thrills to the i8 range, but can it justify the $30,000? premium over its hard-topped sibling? Tell us your thoughts in the comment section below.