iRacing has a very good internal LFE subsystem. It definitely has some limitations (most notably single-channel), but out of the box, it works very well, and with a simple config file change (to play physics effects only), it's pretty much perfect for my use case. I don't even bother running SimHub alongside iRacing anymore. A similar plugin included in rF2 would eliminate the need for an extra piece of software. Just a simple: What device do you want the audio to play on? How "loud" should it be (-x to 0)? (optional) Do you want to enable or disable each effect? (optional) Are you using multiple channels (front/rear, left/right, corners)? The optional stuff may be out of scope... I'm really proposing something that's just good enough not to need SimHub. People who want to tune individual effect frequencies, effects beyond suspension physics, etc. should definitely use SimHub, SimVibe, SRS, etc..
LFE, or Low Frequency Effects, is a dedicated channel for bass effects. These tend to be felt more than heard, and so they're routed to either subwoofers, or in the case of a sim chassis, bass shakers like the ButtKicker. The effects range from merely immersive ("ca-chunk" when shifting) to informative (vibrations when running over a kerb, letting you know that the wheel is right at the edge of the track without taking your eyes off the next phase of the turn).
