The slimline should be pretty decent as long as it is not fitted with the smoke coil. Mufflers like the b&b and Abell will outperform it a bit, but at the cost of significant noise gain. I run the slimline w/o smoke coil on one of my 62s, and have run it with the 23x8 and 22x10 xoar thus far and have no problems getting it into the 7000's. If you need the weight up front, AND CANNOT move other equipment further forward to assist in balancing, don't worry about converting it to EI. You'll end up at the same weight, and the power output of the 62 is the same either way. If you can move equipment to balance, converting it will save you weight, make the engine easier to start (no spring starter either), and thus give you better power to weight. Good looking plane!

Chad