OK........all burp classes go by amp power and how your setup is
If you have all stock seats in and box below window line your in stock.....dependent on class after that from amp power at 4ohm
0-600, 600-1001, 1001- 1801 etc
Now if you have a wall, box over window line, 16v, backseat or something out of ur vehicle youre in mod class
0-1000, 1000-2001, 2001-4000 etc
Now the class that goes by subs is Street Beat, exactly like bassrace cept you go for all out SPL on 30sec of music
SB1 - 2 10s, 1 12s, 4 8s
SB2 - 4 10s, 2 12s, 1 15
SB3 - 4 12, 2 15s
SB4 - 4 15s, 1 18
SB5 - all subs and up
Any other questions i havent answered please feel free to ask, ill let you know what class your in
Whitlee sound shows is the one that goes strictly by sub inches and vehicle type