I use a BR 180SC in my iron liners and 240AO in my plated aluminum bores. It's an easy thing to do yourself, just don't go hog wild in the bore (you just want to remove the glaze and x-hatch). BR flex hones come 10% larger than the size you by. So if you have a 2" bore and order a 2" hone, the hone will be 2.2". Some people will will tell you to order a brush 10% smaller than your bore so the balls won't go to far into the ports, but the tech I spoke with at BR does not advise this as you do want some pressure. Just use the closest size hone available to you bore (they are avail in .125 increments). The AO (Aluminum Oxide) are not as common and mine had to be made at BR after I ordered it so it took awile. At $25-35 one use will pay for itself though and they last a long time.