Do this if you want a slightly richer AFR for cheap!

[Preferio]

Iirc 10.0-10.5

Ms3 runs in the 9s stock but it's direct injection so it's a bit different

My wideband reads 10.0-16.1 and on the stock tune it buried it at 10.0, so I guarantee it's mid to high 9s.

 

[Preferio]

A quick search yielded 10.5 as the stock AFR without the flashed ECM. I never saw that... Always buried it at WOT.

 

[Sport23]

10.5 may be correct. MSPs tend to learn positive LTFTs (which is applied in closed loop.) You could reset your ECU and see what it reads.