Re: the one time i impulse buy... (chinese motor kit)
Definately ditch the fenders, trust me. After I made a beefier mounting tab the fender itself cracked. Get a set of Wald fenders, about $30.
Don't try to modify anything right off, just get the motor mounted and the bike running reliably before you try and make any modifications. A lot of newbies to this hobby fall into the trap of trying to modify and "correct manufacturing flaws" that may not even be present. Get some experience and some miles on your motor before you do anything.
I can't stress this enough, GREASE THE REAR HUB! Mine completely failed after 250 miles. You may want to invest in a set of heavy duty rims, I got mine from my local bike shop for under $70 for the pair.
Keep any eye on the seat stays, they cracked on my Cranbrook after about 1000 miles.
Oh and you can get 12' of #41 chain from Tractor Supply for $16.
Straight tubes suck, the beauty is in the bend.