20c 4s lipo or 30c 3s lipo??

[T-Bro]

I have 2 motors that I'm toying with trying to get the best setup for top speeds/drag racing.
Tc3 Buggy or a tc3 wich is 1 lb lighter
Medusa 50mm 4400kv/NEU 6700kv
MGM 160amp esc 16cell/5s lipo
NEU 3s 30c 4100mah/maxamps 4s 20c 4000mah

With the Medusa I had it geared at 78/25 and it ran pretty good with the 3s until the endbell came off during a crash. It's getting repaired now. Clocked at 48 mph
The Neu, I have geared at 78/20 and it runs ok but still gets kind of hot. Haven't clocked this setup yet... but I will today.
I have a feeling after a lot of reading that if I got a lower kv motor 2000kv possibly and ran a good 5 or 6s pack I'd run much cooler and probably get higher top speeds??