Anyway........let us know what the symptoms are apart from the obvious being twins!
Been all thru the issues with mine when i first had it, managed to sort it, did a few mods and got it boosting properly and had it mapped with ESL ecu to 309bhp....had planned to upgrade turbos with hybrids from Turbo Dynamics, but after a UKLegacy rolling road session at Surrey rolling road, the max you will get from the twins after spending shed loads of money was limited to 325-330 max.
With the same (or less in my case)amount of money you get far better results with a single conversion, more possibilities and a better driving car.
I enjoyed mine when it was twins, tho i did have a slightly modified primary, and the kick when secondary came in(it was mapped to changeover at 4000rpm) was pretty awesome, and that was with no vod! But, the kick i get when my 18g's at 4000rpm far outways anything i could hope to get with the twin set up.
All depends what you want your car to do.
Send me a pm with the issues you got, may be able to help.