i have a trek pdx that i want to convert from a 24 to an 8 speed.

http://www.trekbikes.com/us/en/bikes/urban/pdx/pdx/

i have found a crank set that i think im going to buy and i thought i would put it up here to see what people thought.

http://www.vueltausa.com/components/...set-black.html

I am not very mechanically skilled yet so i have a few questions. will i need a new bottom bracket or any other drive train parts to make that crank work?

will this crank require a new chain and if so will that chain work with my 8 speed cassette?

Thank you for your input!