I'm not a big fan of the QG motors; the seem to have a lot of issues blowing head gaskets. I'm not really sure what kind of performance you are trying to obtain. B12's did come with the GA16i from the factory, so installing a GA16DE wouldn't be too hard. You'll still have to swap over the ECM and wiring harness to make it work. There are turbo kits for the GA16DE if you want to push a bit more power out of it, but I'm not sure how expensive they are to get in your country. In the USA, the go for around $1500 US, last time I checked. The SR-series engines have even more power potential, but would be a little more work fitting than the GA16DE.