Mechanic at a dishwasher plant, in the past I have worked at a yamaha dealership and before that electrician. Where I work now I do electrical, mechanical, hydraulics, pneumatics, and some machining.
I've been running them at .20 over for a couple of months and they add more mid to top end power, you can feel the difference but it is not 8 horsepower on stock ports. I would buy them again but never beleive an advertisement on hp numbers.
Where I live for the same price will get about 2 gallons of 110 race fuel. The octane boost only raises like .01 points like everyone says, plus it gums up your head.
I tried to resolve this over email but could not. Just thought I would share my experience. I bought a pro design billet shifter for a banshee, 40 bucks including shipping. Shifter looks just like it did in picture but does not fit my banshee, it is for another bike and will not clear the stock footpegs. I emailed and he said he used it with aftermarket nerf bars and had built in pegs. I responded that I can not use this product and would like my money back and I would return shifter. It is monday now and have not had a response back since friday when I asked for my money back.
I would feel bad about selling one unless I state the known problems to the buyer. I sure hate to spend the money and then the guy come back a week later because something I was hiding. If it needed a clutch I would put one in or a topend before I sold, but that is just my way of looking at things. Me personally I bought new because of not knowing what to look for at the time, but now I would buy used and I'm going for a test ride first or no deal.
Dlnoss will work with you if you call or pm him about what domesw to run but you need to tell him your elevation and what fuel you plan to run. Have your cylinders measured by the person that is going to bore them and then buy a whole top end rebuild kit that includes pistons, rings, gaskets. How much are you wanting to spend?