If the ign you have now is doing its job you may not see any performance gain at all. Dont matter if you have 35k or 65k firing your plug as long as the 35k is enough to fire the plug in your cylinder it will do the job fine. Once the mixture ignites right 40,000 more volts wont make it work any better or go any faster. If you have a problem then yes you might run better but unless you have a missfire from lack of voltage for one reason or another and its a basic street/strip car I dont think you will have a performance gain. I guess what I am saying is that if your ign can give 35k and it fires all the plugs in your eng fine upgrading to a system with a reserve voltage to 60k wont help as the ign will only use the voltage it needs to fire the plugs.
My son switched from the MP orange ECU to the MSD 6A box and from the Acell Super coil to the MSD coil in his mid 11 Dart and ran no different at all. His old setup with the Super coil and MP ECU did the job just fine on his car and the MSD had zero performance difference. Nothing wrong with upgrading to a better ign that might fire your plugs when they get worn or half fouled better then your old ign but if your old ign fires the plugs fine normaly you wont see a performance gain. The good thing about the MSD modern ign is it can fire a worn plug your old ign may not or if you have plugs get gapped to wide by mistake the new MSD may still fire it when the old ign my not. I actually use my sons old Acell coil and MP orange ECU on my 63 which it works fine running 10's shifting at 6200 rpm.
I am just saying dont hope for some big performance gain if your old ign is working good. Ron