Based in Banbury UK, Theon Design is among the companies building Porsche 911 restomods. It now reveals the ITA001 commission for a customer in Milan.

While this looks like a 911 from the 1970s, the basis is actually a 964-generation Carrera 4 coupe from the early 1990s. Theon Design replaces the body panels with carbon-fibre pieces to save weight while retaining the original appearance. The lightweight parts contribute to a svelte wet weight of 1,152 kilograms (2,540 pounds).

Gallery: Theon Design Porsche 911 964 ITA001 Commission

Power comes from a 4.0-litre air-cooled flat-six engine that makes 400 bhp at 7,500 rpm and 315 pound-feet of torque at 6,250 rpm. The mill gains independent throttle bodies and a drive-by-wire throttle. The intake plenum is based on the one from a 997-generation 911 GT3. The exhaust has a ceramic coating.

While the donor vehicle is an all-wheel-drive Carrera 4, the ITA001 is rear-drive. The six-speed manual, limited-slip differential, and brakes come from a 993-generation 911 RS. Theon Design modernises the Porsche by adding dual air-conditioning compressors and an electric power steering pump.

This car rides on five-stage adaptive dampers and has a nose-lift system. The wheels are an 18-inch Fuchs design with a champagne finish.

The ITA001's buyer selects comfortable "touring" seats for the cabin, including small spots in the back for carrying up to four occupants in a pinch. The upholstery is brown, tobacco-coloured leather. The additional, modern touches include a wireless charging slot for a phone on the woven leather dash. The six-speaker Focal stereo supports Bluetooth.

A Porsche 911 restomod from Theon Design starts at £380,000, which does not include the donor car or shipping. Each build is unique depending on what the customer wants. The assembly process takes around 18 months to complete.

Previous builds from Theon Design include the BELL001 for a buyer in Belgium. It has a supercharged 3.6-litre flat-six making 400 bhp and 367 lb-ft and uses the original five-speed manual gearbox. It weighs 1,265 kilograms (2,788 pounds) wet.

Before that, there was the purple CHI001 with a 4.0-litre flat-six making 400 bhp and 350 lb-ft. The vehicle used a six-speed manual from the 993-generation 911. It had an active rear spoiler.