Im going with the yardsport
 

I have a yardsport YS200 with the GY6 150 in it. I also have a G9 Yamaha gas golf cart. I only have room or time for one. After going back and forth I decided to go with the yardsport. The Yamaha just does not handle the gravel roads without some major modifications $$$$.

I would like more low end toque with the 150. What would be the recommend springs of mods. Not to concerned about top speed. I get about 25 or so now. The golf cart I got it to get about 18. Speed is not my thing. A little better on the low end would be nice.

Never heard of that buggy but the basic buggy with external reverse run about 32 mph stock and internal reverse runs about 40 mph. Knowing what you have would help but the most popular mod is 12g rollers 1500 torque spring, ditch stock air box replace with UNI air filter and rejet carb. It's critical that you know your compression for if low mods will not do much.