If the new unit is the same size, there's no problem. But if it's bigger, you're going to have an exercise in PVC plumbing. I THINK (and I'm not the plumber here) the LEAST restrictive way would be to cut the right upright down a bit, use a 45 deg Sched 40 elbow to move it out and another to straighten it back up to vertical, then fit as needed. Two 45s should have roughly no more resistance than one 90deg elbow. I would think you could pick up 3" to 6" more horizontal room that way.