Like Taterhead, I also have the Wolff 22lb spring and steel guide rod for my G20. I bought them as a set directly from Wolff:
SKU# 50122 Cost is $29.95 for the set, plus shipping.
I haven't had any reliability issues with mine. I even use it for carry, and it works with my 40S&W conversion barrel, too.
Don't really know why some Glocks don't like them and others don't care. Some have said that flat springs work better. YMMV.