The SE when it first came out had a slimline.... which several didnt like, they were noisy, didnt seperate very well, and EMI seemed to affect them more. After the first year thou i believe they improved them. However, if you are talking about the standard that came with the Ex II, that those were selling for top dollar before the Pro came on the market. Excellent coil. An inch in this hobby is a LEAP. The pro coil hits harder on targets, seperates better, is as light as the slimline, and for a larger coil is as sensitive to small targets, also more sensitivity can be used with out the affect of EMI in most areas. These were really a big improvement when ML kind of took a step back with the slimline. BUT.... if yours hadnt came with a pro and you could get your hands on the Ex II coil you are still in the ball park by having an excellent coil. Trust me when i say if you want to sell that Pro and use the standard people will trip all over themselves to buy it from you. The Pro and the SEF have established themselves as and improvement....i think the finds tell the story.
Dew