Thanks for the info, accelerator is expensive 
Amiga is not a cheap hobby.
Simply replacing your 68000 with a 68010 chip (about $5 bucks on ebay), which it sounds like you've already done, gives you about a 2-5% speed increase (which is hardly noticeable) and gives you access to the 'Quit' key in WHDLoad.
Beyond that add some true fast RAM, if you haven't already. That's usually good for a 20-30% speed increase over a stock system.