I am considering doing a scavenger oil change on my 02' Dyna. I was wondering if it is really necessary to purchase the kit offered by Rogue. That thing costs over $100 and it doesn't seem to have anything special other than the hockey puck. Can I simply purchase a piece of hose to attach to the return line and leave the old filter on while I scavenge and then replace the filter. Essentially just skipping the step with the hockey puck? I know I probably wont clean out as much oil with the old filter on there but it will probably be good enough. Is that hockey puck something special?