I am planning on using a traditional wax ring. I need to know:

1. Should I leave the current cast iron pipe as is sticking approx 3/8" above the floor?

or

2. Cut the cast iron pipe so the flange sits level or just under floor level.

If I need to cut the cast iron pipe, what type of saw or device would be best to use, i.e. Sawzall, Dremel, cutting torch, etc.?