Again, impeccable logic.
Folks may remember I did the conversion before Legend’s set came out. Did I mention I worked for them? I’m well aware of the work involved.
This thread is on the M3A2 ODS, but it starts out showing what I did to do the A3 conversion before there was a set. It shows just a smattering of what you’d need to do these days. Oh, and the Legend set does not include the Driver’s Enhanced Vision unit. You still have to scratch that as well. The Legend set? Is that with or without ERA?
If anyone wants to do what you suggest - they can save money and buy one of my unused sets. Why? Ummm, because even I don’t use them. 
Then there’s the new track from Jacques, of course. Oh, and the Magic Factory set. Yes, I can how attractive this option is. 
Especially when I can still get the Meng M2A3 for $50.00 shipped.
Sorry, Magic Factory. It’s still a stinker, like much of the features in the complete kits.