Suspension. Well, I have a 2002 KDX 200, with stock springs on front and back, but I am going have to beef them a bit, and I will tell you what's up with that!! I started riding MX with the bike at the local race track, If I would have thaught I would get in to mx at 31 years old I would have got a kx, but a kdx is a great bike to start on. The front springs sould be changed for your weight and the rear. you can buy them per weight for about $130-$150 front and rear. I weigh 200 lb or so
and my stock springs are hard on me; case in point they are made for people who weigh at the most 170. not to say they are poor for us heavy guys, but when you start jumping like you are talking you will find
that it is dangerous. It will give you poor landing control, trust me I have jumped them 6 to 10 footers at 20-40 feet and bounced to the moon and I have wiped out because of it. Good luck have fun and be safe.