Other collets may work, but you may need to use shims to get the correct clutch bell spacing and end play.
The TLR 8X collet is recommended for the Ignite Design RC AE T6.1/T6.2 conversion. The thinner 8X collet allows for more clearance between the clutch bell and spur gear.
The AE RC8B3.1 4 shoe collet is recommended for the Ignite Design RC TLR 22T 4.0 and XRAY XT2 '21 conversions. The thicker RC8 collet provides proper gear engagement for these two conversions.