Air an Rathad goes all electric in this episode, test driving cars from both ends of the market - the Nissan Leaf and the new Tesla Model S. But who gets to drive what? The Tesla Model S has a range of 250 miles and does 0 to 60 in 3.1 seconds. Both Donnie and Murray are desperate to drive it, so Linda decides to toss a coin... The Leaf is the UK's top-selling electric vehicle, but with a range of under 100 miles, it's a city car. Air an Rathad tests its commuting capabilities. And without satnav or mobile phones to assist them, both teams get hopelessly lost in Railidh na Trealaich. They're trying to get to Grampian Transport Museum in Alford, where a vintage vehicle is waiting for them on the track.

Petrolhead Mairi Ross wants to be a rally driver, but first she has to pass the BARS test. She travels from Lewis to Knockhill in Fife to try her luck. Examiner Bob spots a few driving errors and shares some tips. Is it enough for Mairi to pass? Murray is behind the wheel of the new Jeep Renegade. He likes his cars big and beefy, and the Renegade fits the bill. And the Rally has made it to the heart of the Highlands. The scenery is lovely, but the teams are too busy to notice as they race to win this show's challenge. What will they put their wrecks through this time?