Yeah totally, I use my own risk model for calculating residuals for forecasts and optimization. Only use barra for tracking factor exposures since our investor also uses it for tracking our risk. I find it to be fairly cheap but I guess that's just relative to other expenses and pnl.
Yes that makes sense - own model for trading and a risk vendor for validation. I am surprised you say it is "cheap" though - isn't Barra like 80k/yr?