The shaft size on the needle are the same so that is why you do not have to buy a new needle bearing for it.
It is know as the poormans Micon. At the time I bought my Micron it was 2 dollars cheaper than building a poorman's micron like Craig Fraser uses. So I figured Just get the real deal . But right after that the price for the Micron went back up ..
. yeah, the "poor man" part is a bit relative. Craig has taken to simply switching the nozzle to a .2, and keeping the .3 needle. He says he likes the faster paint response more with that set up. If I remember right, he changes the air cap, as well, but don't quote me on that one. I think he also uses a taller trigger from another Iwata model. But, with the Iwata Kustom series parts available, you can simply order a trigger for the Kustom HP-C+ and put it in your "normal" HP.
I put a .2 nozzle on my Olympos HP100-C (the Iwata HP-C's grand daddy) simply because I had a spare .2 nozzle, but no spare .3. I wound up switching it back, since I have enough "detail" airbrushes as it is, but it does work pretty well. But, unless you're absolutely hooked on the larger paint cup, I'd just get an HP-B or better yet, an SB. But, I am partial to side feeds.