The 16T is a pretty big jump from the factory 12T. The 12T is only a 265cfm turbo... practicaly nothing. The 16T is a 435cfm... the 20G, 650cfm. The 14T housing can be machined to fit a Big 16G wheel... one person has done it already. After some research, i found that the 16G, 18G, and 20G all had the same exducer size, the inducers were different. So in theory, if i can machine the compressor housing enough, the 20G wheel should fit.
I really want to keep the 12T side for 3 reasons... :
1. Its a factory fit... on Volvos, you cant beat that.
2. The spool time.
3. It will still look factory. In order to do this right, i have to preserve the cars factory appearence.