thats what i really want to do, but the question is will my stock chain work with the bigger rear sprocket?
Long answer: When I'm due for new chain/sprocket combo I'll be replacing my 14t/45t combo with 15t/47t coz I think it's the better option. I just went 14 up front coz that was an easy and inexpensive way to lower the gearing from day one. When its time to pay for a new rear sprocket, I'll buy the bigger one coz I think thats the better "engineering" solution to acheiving the same end result.
Short Answer: keep the stock 15T front and get a dp 47T rear sprocket.