I rather hope you are a little more mature and more reasonable than you sound. At the risk of another flame, Rob is right about the few MAK90s with the welded up holes, but wrong that they are legal.
Those are contraband and BATF will confiscate them if they find them. They probably wouldn't prosecute as long as the owner bought the gun in good faith, but they will sieze them without compensation.
Of course, if the holes were drilled out, then the owner clearly attempted manufacture of a Title II firearm, which is a felony, even if no auto parts are in his possession.
In other words, if you buy a MAK90 of that type, you stand at least to lose the gun, which would make it about as good an investment as buying counterfeit money.
Under the circumstances, do you really think asking BATF for help would be a good idea?
Besides, as Rob pointed out, there are no legally registered conversion kits or DIASs for the AK family. Legally, of course, a DIAS does not convert anything to an MG; it is the MG. So for a MAK90, any conversion would be illegal, which is what I said.
You assumed I was stupid or ignorant because I didn't tell you about registered DIASs and parts kits. I didn't mention them because they didn't apply to your question.