[Mtucker666]

SA Porsche chassis change - that will be fine
Motor pod, the SA rt4 pod uses sidearms, but so do the slot it evo pods.
Offset. Either no offset or 0.5mm.  The spec sponge tyre is 21.5mm when new, and I think you still have the required motor clearance of 1.8mm if the tyre goes to 21mm with 0.5mm and 20.75mm with no offset.  You need to have have the motor clearance when  you go through tech inspection