i just ordered an 1860 and i was wondering if the weight of poly would slow it down or if it being slicker would it go faster

Depends on how you install it. Bolted on will create drag, hammer rivets will not be as bad as bolts and are lighter. .250" poly will add about 100 lbs or so. Build your bottom out of 3/16" thick aluminum and glue 1/8" poly to it. Adds about 60lbs with no drag. Poly will float so it kinda offsets the weight in the water.

if i glued it on what glue do i use to where i can still jump beaverdams and bounce of the occasional stump and not rip the poly off

I glue it on with 3m 5200. Yes you can still run over objects.

Installing poly to the bottom surface of the boat will not add speed. It will provide better performance on vegetation/other objects and trailering the boat.

Don't know about speed but I will say that I ran 35 mph and the only thing I changed was the cam and added poly and ran 40.2 mph have a hard time believing hat it was all cam.

speed is a function of breaking the friction b/w the water and the bottom of the boat.... poly will help break it but you will loose the advantage due to the weight if you use 1/4" poly in deep water.... in the shallow stuff if will shine and you will see a difference in speed b/c your boat will actually ride higher than it would if it was w/o the poly.

its all about what you run and why you need poly... not a normally needed item on a mud boat