i found you one for 1/3 the price. although, shipping will take longer...
this one has the red cover, they come in black too. basically it's an nt carb, just with a bigger jet, built in secondary fuel shutoff, and a better air intake/filter.
when you modify your chain guard, you can just use some tin snips and a flat file to smooth out the edge. any gloss black spray paint on the edge will hide your cut. i used cheap color place spray paint from wally-world.
you can make do without the guard, but it does serve an obvious purpose.
one more thing, you are going to need some front brakes. they are your main stopping power. a rear coaster brake alone is dangerous. (and it will chew up your rear tire really fast)