Anyone who's not yet bought into the growing trend for leasing a new vehicle may already be even further behind the times than they might have imagined as subscription services are quickly starting to gain traction with consumers and manufacturers. Volvo's new Polestar 1 performance model is going to be made available exclusively on a subscription basis, but Porsche is even further ahead with a pilot scheme in Atlanta already proving to be hugely successful. Not only are buyers signing up to , it's also attracting new and younger buyers to the brand.

Klaus Zellmer, the CEO of Porsche Cars North America, told the Automotive News World Congress in Detroit on Wednesday, "They are much younger than our average customer." Zellmer added, "78 percent of members in Porsche Passport have not owned a Porsche before, currently do not own a Porsche. So the conquest rate is close to 80 percent."

The majority of customers who have signed up to the scheme have gone for the top-tier plan, which does cost $3,000 per month but allows members access to all 22 available Porsche models. A less expensive $2,000 per month option is available, but that reduces the vehicle choices available to the customer.

Porsche originally announced the pilot of Porsche Passport in October of last year, and the first group of around 50 subscribers to sign up began taking delivery of their cars in November.

As well as huge potential for expanding the subscription plan, Porsche is also anticipating further changes to the way its vehicles are purchased in future. The company expects that by as soon as 2025, around 30 percent of all its sales will be made online.

Although Porsche is ahead of the curve a little with its subscription pilot, its success hasn't gone unnoticed and its big German luxury rivals BMW and Mercedes are already planning their own subscription scheme pilots in America. Mercedes is committed to a pilot in a US market this year to help it decide whether a subscription model has a long-term future for the brand. Meanwhile, BMW of North America CEO Bernhard Kuhnt said in an interview in Detroit, that BMW is "most likely" going to test a subscription model at some point this year in a single market in the US.