E receivers always the right choice for electric because no antenna means a much easier install. R304SB-E is your best best. I'd it's say the best receiver in general for the 4PM.

The S-FHSS ones are fine but there are a couple of benefits to T-FHSS (unique pairing to a receiver being the main one, telemetry back to the radio has limited applications beyond giving a value for the voltage going to the receiver).

R334 receivers offer SR mode but then you need to find SR-compatible servos to use it and that really narrows down your options and increases your costs. Plus the E version still has a mini antenna on top which misses the point.

HRS mode on the other protocols is plenty fast enough and fully compatible with all digital servos. People get strangely obsessed with the speed of the protocols and then make outlandish claims about how much better the cars feel when you use them. I'll be honest and say that I have accidentally left my radio on standard speed and barely noticed a difference on track after switching it to HRS, despite it being a big difference mathematically.