Essentially the same circuit
Different cosmetics and cabinet and baffle construction.
The Champ and VC are Single ended Class A amps of 4/6 watts of power
The BF & SF VC, The BF & SF Champ & the Bronco have essentially the same Class A Pre and Power section circuits.
Try the Weber 8125A speaker for about $80.
Much IMHO nicer then the Weber signature or other options