I did a Monte Allums Rectifier mod on mine. I actually modded it twice, the second being a triple rectifier mod. I modded most of my Boss pedals, why? Because it's fun. I haven't done any for while now. Check the Monte Allums (
www.monteallums.com) site. There are other like Keeley, etc..
I heard the MIJ (Made in Japan) is so good no mod is needed. But I haven't heard or tried one.