I don't mean to scare anyone, but as one of the few in Australia to pop an engine I have a little knowledge about this.
I've seen 2 engines that have gone bang now, and both have had the same thing happen. Bent conrod 4.
One bent and we stopped tuning it, the other bent and ended up coming out of the block.
Both cars blew on the dyno, but funnily enough one (mine) was making 185kw atw before it blew and the other was making 175kw atw.
The second car blew when it was only running 15psi!
All this crap about there is a problem inside the ECU and stuff is simply rubbish! The sheer fact of the matter is that they are not designed to push big power like the EVO's/WRX's(although the 2.5L WRX has serious limits too..).
Most people here are not really pushing big power, just bolt on bits and peices(exhausts intakes etc..), but when you start changing the turbo you really start to effect the load on the engine and how the car operates.
I was talking to the guys @ MPS Garage and they advised me that 180kw on a MPS 6 is the max they would go, and 200kw on a MPS3 is safe. Anything above that is getting to the limits of the engine.
Having said that, I know there are people running around with 200+kw in a MPS3 with no problems, but it really comes down to the dyno that it was tuned on(some dynos produce higher readings than others).
The point i'm trying to make is if both engines break the same part of the engine then it highlights the weakpoint of the engine. If you want to go for big power or above what i've quoted be prepared for things to go wrong.
As doug put above, you run the risk of damaging the longevity of the life of the engine the more power you put through them. There is also other things that can help, like not thrashing the crap out of it on a hot day, letting the engine cool down for a bit after going on a run and other things to protect the car's life.
Also, from my experience the standback was the only engine controller that cut it for me. Not saying others didn't work, but for me it was the only one that actually did everything I wanted it too.
CorkSport FMIC with Cold Air Induction, , Cork Sport Cat Back, CPE Standback with PNP, TurboSmart BOV, Custom Highflow Cat with CorkSports Downpipe,Pauter Rods, CP Pistons,ARP Head Studs, BIGGER TURBO COMING, Pre-ordered a Stage 3 CPE Engine.