On a stock bore 525, even with 12.5/1 Piston and Carb boring, the Thumper Stage 4 Cam will be too much. If you were to do head work, porting, BB or Stroker crank, then I would probably go that route depending on the build specs you want. The 8/33 on your current specs would be a better way to go.
Also, remember if you go with the Stage 4 Thumper Cam, you will be required to upgrade your valve springs at minimum. With the 8/33 Cam, I would still upgrade your springs to be on the safe side but it may not be necessary.
The 8/06 with 12.5/1 Compression and Carb boring, is a solid drop in cam (that does not require spring upgrade) that will give you more mid and top and with the compression boost with the new piston will compensate for the bottom end loss.
Just my 2 cents......