so i have a few questions on the technical aspects of riding. i really wish i just had a pro friend to ask these questions, but for now you guys are my pro advice giver. so onto the first question

does the angle of the handlebars affect anything? maybe in how you lift the front end or landing or anything, of is this just a preference part of biking?

what are the differences between 4 piece and 2 piece bars other than structural integrity?

does anyone ride an 18 tt just because its smaller and lighter, or is it pretty much standard to just ride 20 tt's?

how much do stems affect riding? ive seen a good variety of stems and i was wondering if the different ones actually made a difference other than looks.

and heres the last one, having to do with setting up for tricks and stuff. when your feet are leveled out on the pedals, having your left or right foot in the further forward position is just preference right? doesnt affect anything?

alright thanks guys for help you can offer me. im still learning a lot so i always have questions. some that dont really come up in "Search"

also, any tips on doing a manual? or is it just keep trying to find that balance point and just practice holding the manual with your knees?