3 port or 5 port
I have quite a few engines, 3 port, 3 port modified,5 port,and 5 port modified.
If you get a good 3 port engine, the power difference from the 3 to the 5 is not that much difference.
I have a couple of 5 port modified Novarossi engines, and even though they are very fast, I just picked up the new 3 port Orion engine for about 1/2 the price of some of my 5 port engines, and the Orion Wasp will easily run with my 5 port engines.
Do yourself a favor, save a lot of money, and get a good 3 port. Plus, you will be able to run in the sactioned races. I only use the 5 port, and the 5 port modified engines on the weekend for club races, and other than that, they sit in a box while I run my 3 port engines.