it's a tough call, but what you have is basically an entry-level Colnago, built by the same (or one of) builder but out of Aelle to offer a slightly lower cost. I'm not sure what you mean by the "seam" that is separated: do you mean the tubing itself is opening up? If that's the case then you'd really need to replace the DT and a competent job would be at least $150, likely more...and then you need paint. If it's just a buckle in the tube, I'd build it and ride it to decide if it handles well and go from there. I don't think I'd spent $$ on a tube replacement if it were mine. Otherwise: the uncompromised frame probably rides just like a 'Nago.