CREATE TABLE table_16731248_1 (bypass_boosters VARCHAR2, spi VARCHAR2, exhaust_ports VARCHAR2)

How many bypass boosters are there on the engine with slit exhaust ports and SPI is yes?
SELECT bypass_boosters FROM table_16731248_1 WHERE spi = "Yes" AND exhaust_ports = "Slit"
SELECT "bypass_boosters" FROM "table_16731248_1" WHERE "Slit" = "exhaust_ports" AND "Yes" = "spi"