VR! It's what brought me back after a 13 year hiatus. I always struggled with having a good feel for what the car was doing and where everyone else was around me even with wide screen (and the three screen hacks available in 2007). But the moment I tried the Occulus Rift, everything changed. Being able to change my head position even minutely gives me such a better sense of distance and handling.
in 2006, I tried building a racing arcade business around Live for Speed and Force Dynamics' 6DOF motion platform. Sadly the economics didn't work out.
I still love that platform and would love to try it it with VR, but it's just not something I can afford as a hobby driver.
Even having used owned the 301, I feel that VR is more immersive, as least for me. I suppose my sense of motion is more heavily influenced by eyes than inner ear.
Second most important upgrade were the CSL Elite load cell pedals. I think the key is less those pedals in particular than going from potentiometer to load cell. Before load cell, i had a hard time with being consistent about braking pressure and locking up the wheels.