Put it all on a subframe and bolt it to the existing chassis
Idont think it’s a good idea. You will have to do a lot of cutting. The bay engine bay will be big enough but the roof is to low.
.You will also will loose weight balance as the transverse engine will have a lot of weight high up. You will need to remove the spring plate/swing arms and install a Mc Pherson type suspension.
You will be much better of using a Subaru or rotary engine ---much easier fit and enough power
Then there is the roadworthy certificate issue. It will never pass in my area as you are not allowed to weld on suspension parts
This guy did it on a plastic Porsche and although he didn’t used a vw pan that chassis operated exactly like the vw rear end .
Ten when you are finished you have to deal with this
Cheers baron