screw those guys, the only difference is that they have ported something. i ported my 103 jug out and grabbed up some HP. so i'm in the club now!
i have been using this shitty harbor freeight 12v stone carver thing. it is the worst. BUT, it's slow crappy nature has forced me to go slow, slowly removing small chunks of metal. when you work on aluminum, i find that a tile grout removal bit is the only thing that doesn't get fouled by aluminum grinder gunk. but if you put a grout removal tool in a new, fast dremel, you shouldn't turn it up past 3. mine had 6 speeds i think. it works too good.
bits i like: grout removal, ripps out big chunks quick. then sanding drums. i got a 100 pack of them for 15$ on ebay. i use the small ones, 1/4 inch ish. maybe a few different shapes of those diamond grinder bits, for bump removal. then, a few different grits of sandpaper. the kind w/ cloth in it a big +. i got some tiny files from a gun show. they are ok. i really really REALLY wish i had a dentist's drill. and a good milling machine, i do have a crappy one.
i been running stock since i was 16. this is still my first kit but i have had it blasting for a good while now. no blow ups. same ring. brown plug. i got it with the intention of learning stuff.
the 70cc piston port treat kit can be made to smoke polinis. maybe not super ported out polinis w/ 4 petal reeds. but you know. converting elbow grease into horsepower is the most satisfying mod you can make.
when i was sanding my 103's exhaust port, i told my gf that every hour i sanded it, it got 1/4mph faster. i wasn't totally kidding.