Hi beer,

The MMods Stage 5 5 port is one sweet motor. The Stage 5 although it has more overall power, actually is a little softer on the bottom end than the stock version. This is done to make the motor more tractable and easier to drive (especially in buggy). It is acheived by changing the engines timing as part of the modifications.
I run the Stage 5 5 Port in my buggy and it is a great buggy motor. I run alloy shoes with 2 x 1.1 springs and 1 x 1.0 spring and 10% exponential on the throttle and it drives very nicely (on my track anyway).
In Stage 5 trim the 5 Port has heaps of power all around, with extended top end that pretty well matches the 7 Port.
I have heard other modders say that the 5 Port modded correctly is the best buggy motor in the GO range. I am not qualified to comment on that statement, but I would highly recommend it

(It is also the base motor for the new MG66 to be released soon, which speaks volumes about the original 5 Port motor in itself).