brakes are up to you unless required by state as posted earlier. The 45" is fine for that rig unless your in 4 footers all day. The prop sounds ok it depends on what you like, but Im assuming it wouldn't be on there unless it worked, As far as upgrades good electronics are expensive these days, But if you buy welcome to the CLUB!!!!!!!!!!
I have a 2008 183 Elite in my area for sale if interested in lookin PM me