Rear sprag

I'm currently putting together an updated A4LD, basically from 2.9 to 4.0 specs, and I'm wondering what to do with rear sprag, currently it's the spring and roller version.

Is there any information or first hand knowledge on how much better a sprag from 5r55e is, and how soon am I going to run into problems with the spring and rollers type (would anyhow put in new sprag)?

The issue I'm having with the update is that I would need to also update the inner race to 4.0 size...

Or can somebody confirm that it would be possible to use 4.0 sprag race in 2.9 case, is the internal diameter the same?

I have never attempted it so personally dont know. Transtar has different part number for the two races but they dont give any specs.

Here is a link to Sonnax, they have a tool helps with the replacement of the race, maybe message them.

http://www.sonnax.com/parts/2214#tabs1-instructions

In case somebody else is wondering the same, yes, you can use a 4.0 rear sprag inner race in a casing meant for springs and rollers.

You can also use the 5r55e reverse drum with other parts from A4LD, just leave out the washer behind the inner race