Re: Sorry, I'm new here...
#1; mostly the same till you move up to the big $$ engines .
#2; in hind sight I would go with a 7 speed comfort bike with a 4-stroke, auto clutch, jack shaft set up . It seems to be the best rig for having a bike you can really use (imo) but will cost more money up front. Look around the supplier links here, there are some nice set ups.
#3; I think there are a fare number of folks here that really do use there bikes. As with all things, buy the best quality components you can afford .
#4; use the forms Google Search !! There are tons of posts on any topic you can think of . You won't have worry about being a pain in the butt or waiting to get your answer.
#5; Have Fun & Good Luck !