#54= AE#1
#55= AE#2
#56= AE#3

AE pistons are two hole
Losi pistons are three hole

An AE #2 cannot directly compare to a Losi #55 because of hole quantity (and piston OD).

Drilled holes are smaller than molded holes (holes in kit pistons are molded). A #56 drill bit wobbles slightly in a Losi/AE molded piston. The same bit will fit tight with no wobble in a drilled hole. The feel difference between a drilled piston and a molded piston is similar to half weight oils (2 hole pistons).