Theres alot of low end power to be had with a bigger carb/pipe and a well tuned clutch on an e50. Easy to tune as well with a speedo and digital tach. My 2 favoite setups:
1.) Stock 2 shoe lightened to 75g per arm by means of lopping off the far ends (away from the posts) and making a sort of box shape. I run stock springs in em and they launch at around 5000-5500 rpm, hang there for a few seconds , and fully engage the clutch bell (1:1) at around 25 miles an hour. U can manipulate a good 5 mph of engagement (and several hundred rpms) either way just by adjusting spring tension.
2.) Find a 3 shoe korado clutch, the ones with double the length/amount of clutch material on each shoe. Remove the run-out pins and take 2 of the shoes and toss em on a 2 shoe plate. I lighten these to aroung 80-85 grams by means of drilling out 2 holes towards the far end from the pin. For this setup I run the kickstart springs. Gives a much different feel to the launch. Alot more grab per revolution I think? Yet still allows good slip to 25ish mph, but u need the stiff spring to hold back a heavier shoe. Only reason i convert the korado ones from 3 shoe to 2 shoe is the additional weight from the 3rd shoe, post, etc, wont give me the same launch.
Both these mods let you slip right into the powerband of most pipes, so you dont have to struggle through the crappy low end of many kits/pipes that are designed for higher mid-top speeds.
Also, regarding longevity, I'm a big dude (230ish). Ive ran both of these clutches on different setups for a good 2 solid years of a maybe 2000 miles a year? so they definitly hve some mileage on them. All i have ever had to use is atf type f. I change it every 200-300 miles or so? It's usually pretty nasty by that point and begins to slip differently. (edited)