I'm not advocating forged internals for MS3's that don't have bigger turbos, but one reason to consider it is that if you are running high boost levels and some form of ECU tuning (Standback or AP, etc.) it would give you a margin of safety if you do get a little to lean on your tune or if you are spiking a bit on your boost.
It would not be a license to do anything stupid with your tune, but could keep you out of trouble if your tune is close to the safety line.
There is the risk, however, that if you or your shop don't do the upgrade properly, you could be worse off and end up with a failure because the install (basically an engine rebuild) was not done to proper specs. I do not see this creating any more power for you -- unless, you were to blueprint the engine at the same time.
You can pick up considerable power gains with a blueprint -- precise balancing of all rotating mass, equalizing the weight of all moving parts, exact indexing of crankshaft journals so that every cylinder comes up on top dead center at exactly the same number of degree of spacing, by properly eliminating any variations in deck height (how high up the piston comes when getting to top dead center), by making sure that cylinder volume is equal for each cylinder in the head, etc. You'd be surprised at how much minor variation there can be in manufacturing tolerances. There are lots of tricks that can be done to a completely stock engine to eliminate sloppy factory tolerances. This can translate into significant horsepower gains. But this will be expensive. A good shop will know which side of the tolerance range will be the most beneficial for power gains without sacrificing engine life and can equalize all of these specs -- at a cost.