You can make real world power by simply reducing the losses between the power stroke and contact with the road surface. All contact in this world of ours results in friction. Friction has a cumulative power loss effect. Transmission requires varying amounts of that precious power you created in the combustion chamber to transfer & convert that carefully crafted & often expensive power stroke, into heart stopping drive! There are various ways-methods & processes to make your transmission more efficient including coatings like DCL ( diamond-like carbon coating, and is a nano composite coating that has unique properties of natural diamond low friction, high hardness, and high corrosion resistance) or much more efficient designs like cross cutting etc but ........all manufacturing even in this technologically advanced modern world of ours has tolerances. You often see tuners - engine builders etc on various tele shows handling transmissions, spinning the various gears & sliding them up & down the splines. The above pictured is 2 sets of identical super bike transmissions but with selected pick & mix i made a better set out of the 2 & increased RWHP BY 3HP on the same bike. You can buy second hand transmissions or swap borrow between friends or in Main dealer terms share parts & juggle the best - smoothest into one set. An example, a British Super Bike engine builder, use's 3 engines to build one stock motor for the season.