nobody has done a twin turbo setup because:
1) No room! My single turbo BARELY fits as it is.
2) No more gains than a single turbo
3) Its purely for pimp factor and most people are NOT going for that.
4) Unless youve got funny money, the cost to fabricate a TT kit is going to be rediculous.
You might as well just buy a noble because its going to cost a buttload to make it happen on a contour.