I don't think the radio is overkill, no, I have a 4PL and I still use it and like it, despite having an Airtronics M12 that I race with. I started with the 4PL and it served me well for the first racing season. No complaints, other than a fragile external antenna (so be careful not to break yours).

For any stock (often called "blinky", since the ESC will blink in stock/basic settings, so no boost, no timing advance) racing I can honestly recommend a Hobbywing Juststock ESC. For $50 you get a very solid ESC that will be competitive anywhere. If you have a bigger budget, I personally love my LRP Flow, smooth as butter and super reliable. ORCA is another brand to consider, as they are quickly becoming very popular (at least in my area).

The servo will also serve you fine, no problems there. As for motors... you can go with something as cheap as a TrackStar (which is now ROAR legal), all the way to the more expensive brand names like Reedy, Thunder Power, Trinity (RevTech, D4, etc.), ORCA, Orion, etc. These days there are a ton of good choices, just hang out on this forum and you'll learn a ton.