Yeah, this thread is pretty damn funny. First of all, your car will never come close to replicating a rally car engine/exhaust sound based solely on the fact they are running a backfiring system/anti lag system. They constantly keep the turbo spooling in order to reduce turbo lag. They basically constantly throw unburnt gas down the exhaust manifold when the throttle is closed which ignites on the hot manifolds and keeps the turbo turbine constantly in motion to avoid turbo lag meaning a completely different engine management system and exhaust note is produced. Even if you do purchase an aftermarket anti-lag kit for you car, it still will not work the same as a standard rally car system for backfiring. The aftermarket anti-lag system will just retard engine timing to produce a rich mixture compared to a rally car system which normally have fuel injectors that spray directly into the exhaust manifold. You might aswell learn something about engines before you modify one so you actually know what the hell you are changing and the results that will come from it.
For the chumps in this thread claiming that they have friends with rally engines, you are foolish. Those engines are such a high tolerance they cannot run pump gas, and are tuned specific to run a certain fuel, not just some bullshit racegas you purchase aftermarket. I deal with this kind of shit for a living, I am a mechanic for a higher end german car company.