How doo the self ballasted MV work? is it the tungsten filiment? hmm, i would like to know,and where a site would be for me to read.

The tungsten filament limits the current to the arc-tube, similar to a ballast, but in the process creates light output in addition to the arc-tube. Here's a site that shows different lamps.

For 230V area it is just the tungsten incandescent filament in series with regular MV burner (2 main electrodes, one or two auxiliary with their resistors).
In 120V areas the assembly is much more complex: burner has preheat filaments and in the outer is a bimetalic switch controlling the preheat (bypass main electrodes by series combination of preheat coils, what heat main electrodes to allow arc ignition on 120V when he bimetal switch heat-up and open), because 120V OCV is not enough even for starting probe to work correctly.
The filament is indeed the ballast, as it is the only known ballast technology capable to withstand such close burner proximity, so possible to integrate into common outer bulb.
At the same time it add red part of the spectrum improving the color, but as well as the infrared. The latest is responsible for the rather low overall efficacy.
It was made as an energy efficient replacement for long lasting incandescents: It has similar efficacy to regular 1000hour rated incandescents (and/or 2000hour halogens), but the life of 8..16khours. Incandescents with 8..16khours life rating have 1/2..1/4 efficacy of the regular 1000hours life rated equivalent, simply because the filament is run colder, so the return to normal 1000hour incandescent efficacy is actually 50..75% energy saving.
Using today's technological and energy cost optics, the "decent", but more expensive solution of using standard MV (for extreme long life and/or when the switch is close to the fixture) or CMH (for highest efficacy and better color) with remote ballast pays off.