Racing will 100% make you a stronger skier, but I think its really their mindset that makes the transition to park so easy for them. My only experience with racing is a few christmas and march break intro camps but they push their skiers really hard, and racers are very confident and driven. They have a very competitive mindset and are always looking for that next big trick. One of my friends quit racing and after a year of park was throwing rodeo 7's, switch 9's, and misty's of cannons. Racing will give you a great place to start skiing park, but obviously your coaches aren't going to teach you cork 9's.