Are they difficult to replace? I have the Ferrari ones, and I tried on almost a dozen pairs today looking to find something else I might like...but everything I tried on was either too big or just didn't fit/feel right. I was hoping to get something with spring hinges, but I didn't find anything I like. The only thing with spring hinges (aside from my Pennys) that I like are the Square Wire 2.0s. I might try the Half-X. BUT...I think I will try and get my hands on an black pair of Blades with BIP lenses. I saw a pair of lenses for sale and thought about just replacing the lenses in the Ferrari frame that I have, but I think that's going to be a pain in the but every time I want to wear red for driving, than black for when I need to get dressed up. If they are quick and easy to replace, I'll just get the lenses...but if not, I'll try and get a new set all together. I got the Ferrari ones for $140...I could have got the black ones for $120, but I don't see them available for so low anymore. So get replacement lenses...or spend the extra money and get a new pair? I don't see replacement lenses for sale on the O site, can you buy replacement lenses for the Blade, or do they have to be sent back? Thanks!