Wheels24's spyguys have captured images of the third-generation Audi TT Roadster being test-driven in Europe ahead of its debut later in 2014. Like its Coupe sibling, revealed earlier in 2014, the drop-top TT will be based on the MQB platform but will be lighter and smaller than the A3 with which it shares a platform.Bar the convertible roof and subtle design tweaks, the TT Roadster looks identical to the coupe. IMAGE GALLERY: 2014 Audi TT RoadsterThe current base engine for the new TT is a two-litre turbodiesel producing 137kW. Audi will offer at least two more engines slotting under that – a 1.4 TFSI with 111kW and its two-litre TDI as used in the A3.Missing from TT engine range is Audi's 1.8 turbo as used in a number of other VW / Audi products.None of these engines seem particularly impressive but in a car that's around 50kg lighter than its predecessor could produce a fast and efficient cruiser. A 230kW TTS Roadster will also be launched, capable of 100km/h in five seconds and a limited top speed of 250km/h.