727 or 904

I have modified my 727 with a transpack and a good superstreetfighter stall and I am really happy with the result. I am planning to use a 727 low gear set to get more power from my set up.

Don't forget that you will also have to change the driving shaft, buy another stall in addition of having the 904 rebuilt. I don't know ho much you pay in the USA, but here, it can cost around $2000 to have a strongly rebuilt 904 with a stall. An aluminium driving shaft can cost $500. Your 727 is already paid and installed...

Does these extra dollars spent for a 904 are worth the 2 thenths on the track? I'm not sure...