The SOB (Semi-Only Board) was made to comply with the NPPL ruling for an OEM semi-only board in 2002 tournaments. But Bob wouldn't take away all of those modes of fire without giving us something back
. The SOB is no longer limited to 14bps. It is capable of around 35bps (realistically the gun cycles around 18bps but now it is no longer heald back by the board). The board also has less debounce timming, creating a more responsive trigger. These both add up to a higher rof.
If you want to see what the LP mod is or how to do it, go here http://www.pettypb.com/timilp.html
. What it does is lower the input pressure from around 280 (after your hp reg) to under 200 (removed hp reg). Less pressure means that its easier on paint, quieter, and has less kick. The drawback is that less pressure, means more gas consumption. Personally I noticed very little increase in consumption, but I've got a 114/4500
. Hope that helps.