Anti-Lag is something that needs alot more consideration other than just the function itself. You need to consider Transmission strength, aswell as the strength of the engine, which is why the overall cost is high.

Omex 600 Series Management supports ALS and costs around £2k fitted and mapped, but that cost doesn't include the ALS map and other Auxillary maps. You also need modifications to the car to allow it to actually produce Boost, which means Throttle Body mods etc.

There are devices on Ebay to simulate the sound, if its just the sound you are after, best to go that way.....