If you want more power, I would recommend simply upgrading your map sensor & upping the boost.

I have tuned several stock b18 & b20 motors to the 280-300 whp range.
They all are still on the road today without any problems.

I have personally tuned on a dynocom dyno (over 50 cars).
They work great, however the dyno can be misleading if the dyno is not setup properly.

I would suggest you throw your car on a dynojet for a comparison.