read ALOT before you try it. best bet would be to buy a motor basket combo and start with something like a 12 or 15. something with a low power rating that you can beat on until you get comfortable with it. this way it will be cheaper.
if your interested i have a dc level 3 motor with a 15 inch basket id let go real cheap
none. few members on here will sell parts. WooferCooker is a great guy along with SSackett, both are awesome dudes. daves stuff is nice as well. i get parts from all 3.
as for magnets. buy assembled motors. i have prototype motors here i had to build and all and it was a nightmare. well one set wasnt bad, but my neo motors are a nightmare