I guess it's possible. I have to ask, however, if you got the Grotech new or used. I ask because a new one runs $600. For that amount, you could get the H&S A-150 F2001 ($50 more). Can you return it?
Assuming you got it used or cheap, it may be possible to modify it. What size tank are you using it on? Although not a needle wheel, the Grotech is supposed to be fairly efficient, so you may not need to upgrade it.
As far as I know, there isn't a needlewheel for the Eheim 1250. The most comparable would be buying a replacement H&S Aquabee 2001 (w/ induction assembly) from Finsreef. The Sedras are cheaper, but are also louder, hotter, and don't pull as much air.