I myself am in the market for a B&K 50 and thought about purchasing a 30 and having it upgraded to 50 specs. Here is an ongoing discussion about this very topic on another forum.
I hope this is ok to post this link here.
B&K upgrades
I just got off of the phone with a B&K tech. I wanted to get my facts straight before responding to you. The tech told me it will have all of the same boards and features of the 50 minus the additional inputs on the back of the unit.
The upgrade from a 30 to a 50 is $498 +shipping cost (usually $20 to 30) if you contact B&K directly and get a return authorization number from them. If you take it to an authorized B&K dealer in your area they will charge you more.
