the bypass of course has to be diy. The stand is a perfect fit from the red dragon big block to the Laguna 2000. I have a red dragon return pump and skimmer pump and a Laguna 2000 sitting in front of me as I type this. Eveything from all 3 pumps fit each other, I gurantee it, I've tried it all.
The Laguna block holes have to be redrilled to fit the red dragon stand and from there, the volute attaches to the stand as usual. Only thing you have to mod is the holes to attach block to stand and mod the bypass if your red dragon has it, my return doesn't, my skimmer pump does.
The impeller from my red dragon return fits my Laguna 2000, and Laguna 2000 impeller fits the red dragon blocks, why wouldn't they fit? The block is the exact same block. Idk which 2000 you're talking about, but my Laguna max flo 2000 block is not slightly smaller, it's identical to the red dragon big blocks. But again, we are talking about the big blocks now. Red dragon has a small block, which is equivalent to the Laguna 1350 and I'm unfamiliar with these as I don't own any of it besides the red dragon 1500 small block that was on my vertex alpha skimmer which I don't have anymore.
the askoll blocks either for laguna or red dragon, as far as I know, only have 2 block design, a big block and small block. I don't get how u say that the Laguna 2000 is slightly smaller than the red dragon block???? Then that means the Laguna you have is a small block not big block. There is no such thing as a slightly smaller block than the big block but still bigger than the small block. All the Laguna 2000+ pumps use the same big block (internally may be drawing more power etc, idk about that) but as far as the outside, it's the same size as the big block red dragons. Again, there is only a big block and a small block, there's no such thing as a medium block. If u have a big block then evrything fits wether it's red dragon or Laguna, and same thing goes if u have small block red dragon or Laguna.
You'd think I know what I'm talking about since I have a red dragon 4,5m return pump, a red dragon 1500 big block skimmer pump, and a Laguna maxflo 2000 pump right in front of me.
But who knows, I'm not an expert only a person that owns these products, so maybe I just got lucky and got the ones that fit, there may be ones out there that don't fit, honestly, I wouldn't know that if there were.