x2 its just not worth it unless you go all the way. Once you get it there though they are great bikes. Make sure you do a cut dome setup and not a spacer plate setup. there more than motor here too,with a proper 4mil if you have a stock swinger you will have a wheelie machine.
4mils can be brutaly fast though. We have a "safe" drag ported 4mil,with cpi inframes,+2 swinger,35mm pwk'sect,ect,and i swear to g on pavement in 4th gear at about 50mph you can seriously flip it backwards at will without pulling up. Its a fun ride