Advice needed

[Bubsbuggie]

Pic 1 is a cart I completed last year. Pic 2 is a Yamaha electric frame that I am wanting to do something with. Pic 1 is a brick wagon. I want something with a better suspension both front and rear. Actually, I think it's the rear suspension on pic 1 that makes it ride like a brick. Anyway, I am thinking of an ATV front and rear end and motor. Any Idea's. Are there other better options available? Is there a min size motor that I shouldn't even consider? Pic 1 has a 23 HP VG - and want something faster. I have even thought about putting in a vw tranny. Pic 3 is a VW that I built years ago.