Yes, you can get a mail-in tune from a number of vendors such as TTP Engineering, Dynoflash, Mellon Tuning, and other leading ECUFlash tuners around the world, all of who charge reasonable rates, have good turnaround and customer service, and more importantly, provide good yet safe tunes.
I think that it is neither prudent nor smart to start tuning your own car if you have not got a complete understanding of how things work. That could turn out to be a very expensive lesson.
To get up and running to do your own tunes, you will need the following
1. Cable : Tactrix cable for Mitsubishi
2. Tuning software : ECUFlash from OpenECU.org (free software)
3. Datalogger : Mitsulogger from Aktivematrix (free software) or EvoScan (commercial, but well worth it)
1. Dataloglab : Log Analysis Tool
2. Wideband O2 sensor : I'm using the Innovate LM-1 to supplement AFR reading in my datalogs generated by EvoScan
I'm not a tuner myself, and leave this to people who are far more qualified to work on my maps, but I understand how it is done.