As everyone else mentioned the OAR should be at -1. Think of this as a percentage, -1 being 100% of timing be added by the OAR table. If it is at -.5 you are only receiving 50% of timing from the OAR table.
When you upgrade to the Cobb tune you really are only gaining power down low compared to stock. Have a look at the dyno graph below, it compares factory tune versus Cobb Stage 1 tune. If you are racing your brother from a roll above 4,000 rpms you aren't going to be any faster than you were before. However if you are running him from low in the power range, the power and torque gains you get with the tune should show. If you are starting from a dig you are probably spinning more.
The turbo itself is one of the main reasons why this car is hard to make power on the factory components. Increasing the flow will add power but you aren't going to see HUGE gains unless a turbo upgrade or more knock resistant fuel is being used.
Here is a comparison of the my stage 1 tune, versus Cobb's stage 1 tune on a completely stock 2015 FIST. The second graph is my E30 tune versus my 93 Stage 1 tune. You can see the extra octane allows for it to pick up some more power up top.
Hope this helps understand where the power is had with tuning on the stock turbo/stock hardware.