upgrading turbo ?'s

[Velon]

still using old school journal bearing turbos ta49, looking to possibly go to ball bearing turbo, what is the main difference, better spoolup, etc, and more plumbing. Is it worth it, I've heard good things, definitely going to a 10inch PTC either 2800 or 3200, seems good to use the 2800 if going with a bb turbo up to 62mm. What is great combo for loww 11's high 10's?thanks