It will most likely be a D14A4 / D14Z4 (restamped A4 with update to make it more economical) however to be 100% sure you can check on the block.
Open Bonnet, look at the front of the engine where the gearbox meets the engine there is a flat section thats got a "D14XX" number, the XX signifies the exacting code. I have actually got a brand new kit with tensioner I bought recently and never fitted because I bought a new engine, let me know if you're interested
I've attached a picture of where you're looking!