Hi, Craig.
I tried the ENYA 60 4S in a C/L plane years ago.
The plane was the original Red Baron which I was using for a 4S test bed.
Very smooth, very quiet and a bit anemic.
Also, as you stated, VERY HEAVY.
Believe it or not, the ENYA 53 4S weighs less and makes considerably more power.
I tried a number of other different 4S engines, ENYA 46, ENYA 60, ENYA 53 (2), OS 70, SAITO 56, SAITO 80, SAITO 62, SAITO 72, OS 52, OS 48 and a Lazer (not sure what size).
The ENYA 53 was the best.