yes you need to pull out the engine, the crossmember is in the way to pull the crank and pistons from underneath.
You need to drain the motor, pull it, remove the tranny and flip it upside down, remove the pan and the take the crank out, pull the pistons out on their rods and snap the rings off, snap new ones on, hone the block and replace the pistons in the bores and replace the crank. since you have the crank out and rods off, you may as well replace the bearing shells on the mains and rods. And since you've the engine most of the way apart by then, you might as well succumb to "while-you're-at-it"itis and remove the head, pull the camshaft and valve springs and lap the valves to the seats and replace the springs.