The SP2P is a real turd. The ports are smaller than a stock 2 barrel intake. You could drop a peanut down the carburetor and block 60% of the airflow in whichever port it went down.
The Performer 318/360 has ports similar to a stock iron 4 barrel intake. The main advantage it has is the reduced weight. It is a better choice than the SP2P by a mile though.