will to start good luck with the car and have fun!!!!!
will the os engine i can not tell you much on but they say its good
for starting out you should look in to a package engine with pipe and header like the new mega engine set up . you get the tuned pipe and header tuned to that engine"s power band so you get the most out of the engine and it good for the price to start out with and learn to tune . and yes its a 3 port with slide carb .
as for the orion wasp i was thinking of trying it too still looking into it too!!!!!
tuned engines are some times a little harder to tune to start out with

1 yes all of the comp racing car us it slide carbs
2 denotes??? don't understand
3 well the ports are the way fuel is let in to the engine to burn and released in to the exhaust .where they are are on the sleeve in the center of the engine.
4 what make's it legal is the it goes by the rules in the rule book . what makes it not legal is when things are changed for inhanced performanced
and take it past what the rule book's state . un less the class is open run with you brung .
hope this help you