Mike,
I am not techie on this and you might want to call Abbey...01883 732331.
For what I know, the stock ceramic turbos should only really be run at 1 Bar max. You could run 1.1 bar or 1.2 bar but you are risking the bearings and internals for destruction as they are not built for this. You are playing with the devil I guess. And broken turbo fins will go into the engine and then it is rebuild time!!
You could run it but you will shorten the lifespans. The internals are cermaic and light and hence spool up quickly. The steel ones will give a little more lag but can handle the boost and you won't run the risk of internal or bearing damage.
As for the kit, then you would need to think about a larger intercooler as well to run more boost to increase the efficiency of the cool charge. Plus the hard pipe kit to hold the boost.
I think once you go over one bar it starts to get expensive and the stock parts have reached more than max efficiency.
Also you start to run into probs with back pressure on the stcok turbos at over 1 Bar and this can lead to them stalling and breaking. Is this right chaps??
Stick to one bar, save the cash and do all the mods at the same time. Might be worth sorting an oil cooler while the front bumpoer is off as well.
For any pics then check out
http://www.takakaira.com and weep!!
Go into Performace parts and click into the TRUST logo. You can get lost in there for hours!!!
Nick