Swaps

[BoostedFC]

Generally speaking Most FC owners tend to not have the funds to do a complete 20B swap. Meaning the parts & associated labor cost. Further more doing any internal mods would be out of reach. A lot of FD owners who do the swap usually have deeper pockets. Piston swaps are popular for a few reasons (cost & more resources) GM LS V8's can be found fairly cheap & have potent power packages.

Now I have to ask since you are asking which would it be cheaper to do the swap in, do you currently own an RX7? If no the FC will be cheaper to start with. Also remember that good power can be had with the 13B & more cost efficient.