The difference is primarily 1 more bearing, upgrade to Anti Rust bearings. The size designations were changed from 250 to 200, 150 to 100, but the size is the same. The old silver 200, 100 were cast aluminum frame rather than forged on the gold, all are now forged. In addition, the drag may have been updated, not sure on that.
The SV versions are only available in 400 and 700 sizes and the only difference is that the SV's do not have a level wind.