Helps only until the battery runs out and is gonna be just normal 1.5L 2 door car.
Yup is not a plug & play to transplant a K20A, most are opt for Superchargers instead.
Depends on how much you willing to spend
Supercharger kits from HKS and Jackson Racing available for the CR-Z.
Basic ones that I see reaches 140HP with the kit.
But like i said depends on how much u willing to spend. More upgrades for the car.
Here is some read for you to have a look. Up to 300PS also got but additional mods of course.
HKS Europe - News
HKS GT SUPERCHARGER SET UP KIT
Thanks for sharing he links, haha. If it can reach 300PS, then it is more powerful than K20A already. But the cost of tuning a CR-Z to reach 300PS is going to be very expensive for sure. Probably cost half the price of a new CR-Z already.