Yes the blue is stronger than oem, but not by much. I don't have one, just going by Malossi information says 106% stronger, which really means 6% stronger. I need to get one. Green is 60% of oem, purple is 82%, and blue 106%. Description miss-leading, before I measured I thought all the Malossi springs were stiffer than oem.
For rough measurement, take an empty toilet paper tube and cut it to the length of the collar seal, approx 2". If you have an extra collar seal, or your driven pulley is disassembled, use the collar seal. Then using a bathroom scale with the paper tube inside, compress the sping down the the height of the paper tube and record the weight to compress it to that height. Do the same with the other springs if you have them. Although not total accurate, I found it consistently showed the relationship, which springs were stronger/ weaker. I verified green weakest, next purple, then oem. I don't have a blue, but will probably get one now, based upon your recommendation.
Cheers