If you were upgrading from a lesser radio (27mhz or something) to a 4pk I could see there being a noticeable difference. The 4pl is not that bad of a radio so I don't think you will see any different going to anything else. I felt like I could feel a difference when I went from a 72mhz radio to a 2.4ghz M11 like six years ago. Recently switched to a 4pks because I was having issues with the spektrum module in the M11 and really couldn't tell a difference in the radios.

All the software features a higher-end radio has to offer will never really be used anyway. Unless you have money to burn for a 4pksr, I would say that you are fine with your current radio