yes there is serious lag off the line. The gearing in a buggy was never designed for such huge tires. I upgraded to a 13/48 ratio and it helped but its still sluggish and engine temps soared over 300 after a couple min of WOT...brake, WOT...brake, etc etc.
I killed a set of brand new clutch shoes in one session running 16/46 gearing.
Ok enough of the bad part. Those tires enabled me to fly like it was a bird and land softly with none of the typical buggy "SLAP!". I was able to pull a double backflip with all that rotating mass to help. Only got about 3/4 the way around to completing a forward flip but i think i needed a bit more hang time and it would have landed properly. Because those tires raise the body off the ground quite a bit you can tackle just about any terrain. I was running through relativly deep grass and all kinds of rough rocks and dirt at almost full speed.
So, if your looking for the kewl factor and want to run your buggy anywhere anytime the big tires rock. If your looking for performance, stick to buggy tires.