Yunus - First off, what is up with your avatar brother? Seriously... LOL
Okay, there is something you need to understand here.
With kits like the Mech Tech, you are not "permanently" altering your weapon. What you are doing is trading some parts for others.
You aren't "illegal" with the pistol, because you have a legal pistol.
You aren't "illegal", in most states, when you make the conversion because you have a "full length" barrel and stock.
The Mech Tech kit isn't a "weapon" - it's a kit that you interchange parts to enhance your weapon.
From their website:
Legal Alert: Our product is not a firearm by legal definitions. The product is for sale to California residents under limited conditions. Although the product itself is legal, as we understand things, the resulting combination with a pistol frame becomes illegal under California law. If you are a CA resident you should be aware of this and it is your responsibility to observe CA laws. At this time we know of no other States where the combination is not legal but we caution everyone to become aware of relative state and local laws. We are not attorneys and can give no meaningful advice on these matters.
Now, you need to check laws in your state. Brett ordered one of the Mech Tech kits for his 1911. Truthfully, it was a neat idea, but it wasn't that impressive in performance.
The frame goes into the kit and remains the same, but the operation is with a 90 degree to frame bolt handle off the side.
Accuracy was improved over the 5" barrel, but it wasn't on par with other 16" barreled rifles.
For a SHTF conversion kit that can give you the chance to drop game, protect the perimeter and still be capable to switch back to a side arm, it's a good choice if you only have one weapon and need versatility.
Outside of that, it's kind of a waste of money in my mind.
Sorry, I don't have the patience to file through all the laws concerning legality, I am just not in the mood.