Hehe.... yeah I do it all myself. Mostly to get the experience and learn. It is my 6 year long experiment. It is my aspiration to tune on a professional level but I do have a ways to go before I am to that level. I'm hoping to get myself into a professional class soon just so I have the credentials to back up my mouth LOL. I am confident to say I know enough to derive a reliable tune but I just need a piece of paper to say that.
I have tuned others cars both in person on the street and over the internet but I limit my self to my car because I don't like making mistakes on anyone else's cars. I am pretty thorough and as a result my e-tunes tend take a long time to derive.
Just to show you how anal I am and the process I use, check out
TD_D's thread. I decided to help him out to this extent mostly because he was having real problems and no one he could turn to locally. I can really only do this stuff for one person at a time. It takes allot out of my already busy schedule. If you want me to take a look at your car I would be happy to run through a live street tune with you but you would have to come out to me.
Another note, I tune everything on the conservative side or the safe side of aggressive. I will not push a tune beyond recommended safe levels.