When I bought my wr426 it had a white bros e-series muffler but with no blank disc to make it USFS approved. I have ordered the discs, screws and blank disc but the blank disc has been on backorder with WB for over two months now . Anyway, luckily the guy gave me the stock can so I put that back on so I can at least ride it and actually it seems to run really well with the stock can but I did notice the WB pipe weights about 1/3 of the stock can. I have a couple questions. 1) Will I notice a big difference if and when I put the e-series back on? 2) I read the 4 discs equal about a 1 inch opening but it will run best with 6 or 7. Does anyone have one of these on a 02wr426 and recommend how many plates to run?