The set I'm running is good for more power that's for sure. Most of the issue comes in the intercooling. If I could keep my temps down, the power goes up automatically. W2A would probably work best for that. Realistically if i went down the W2a path, I should be pusing upto 280rwkw with that turbo.
 
And yes, I have the 255lph walbro (we sell these for $115 each) in there as well, not to mention 265 wide tires at the back ;)

I think the 390KW you are referring to is a theoretical maximum power at the flywheel. So not what your going to get in the real world especially using pump fuel.
 
That side mount cooler would probably handle 250KWs but only for a short period of time. Maybe one blast through the gears and it would be heat soaked. I think around 200-220KW would be its max.
 
And from what I've read about the GTX turbos is that the benefit is only realised when you increase the boost quite high. Running E85/race fuel etc. I could be wrong on this though.  
 
If you want to push more out of the engine move up to the next turbo size. Something like a GT35R. Will be laggy on a 2L engine though. 

This what I used to achieve 316. Had I used a free flowing exhaust an/or a larger than stock throttle body power would be up around 325-330 maybe???
 
Polished GT35R .82 V-Band housing
Tial 38mm wastegate re-routed
Stock ex manifold
Fujitsubo 3" exhaust
RMR inlet manifold with stock throttle body
Wolfkatz top feed fuel rail with 1000cc Delphi injectors
Walbro pump and Turbosmart FPR800 Fuel Reg
HKS 264 cams with HKS cam gears
Port and polished head with 1mm oversize Ferrera valves
Engle valve springs
L19 headstuds
Eagle rods
CP 86.5mm stroker pistons 2.2L
knife edged 5sfe crank
ACL race bearings
ARP main studs
High flow high volume oil pump
VMAX block girdle
Fidanza flywheel
Clutchmasters FX400 clutch
Gen3 gearbox with stock lsd
CRW Upgraded cv joints
Grex oil thermostat
Large side mounted oil cooler
6" K&N filter on a 6" to 4" velocity stack
Tial Q Bov
700x300x100 boot mounted intercooler. Twin 12" fans
AP Engineering Power FC
MSD 6A ignition box
MSD HVC coil
Magnecore KV85 ignition leads
2Ltr Boot mounted oil catch can

No problem.
 
It would most likely cost more than 25K these days as labour rates have risen since the work was done. I think it was around 2008 when I built it.
 
Whatever you decide to do just make sure you do it in the right order. If you think you will go with a big turbo then build the engine first instead of fitting the turbo and then blowing it up on the dyno for example.
 
I got the majority of my parts from Dylmrt. 

+1 for Dylmrt That's who I used for most of my build.
 
-9874558787445 for EMS

Thanks Dylmrt, I'm starting to think the same thing haha.. I think that I'll slowly build it up, forged internals, better flowing fuel system and such, until the day that I can finally get the GT3076 on there and just see what I get.. I've been bitten by the power bug and I probably need to settle it down a little! Haha..

I have no doubt that it will still go when I need it to, and leave most cars for dead off the line! 

Just curious, how does the GT3076 spool on the 3sgte? At what RPM range would you say you reach full boost? 

Haha, you did well to explain it! That makes perfect sense.. 

I am a little worried about lag, but at the same time I understand that by wanting more power its something you have to deal with! And by the sounds of it, it doesn't seem like it would bother me..

Yeah, I will have to see what I can do about getting a hold of one of my parents mates.. I'm pretty sure he owns an MR2 with a GT3071 in it.. It may not be at 250RWKW but at least it'll give me a better idea. And I'll have to trust you on that one ;) 

Thanks dude, you'll be the first person I'll be in contact with! 
Cheers for all of your help!!