I guess its time to upgrade them - its a shame because I have 3 of them that are otherwise perfect with very low meter readings (I cant get genuine toner anymore and now one of them needs a complete imaging unit as its in poor condition)
If you need the modified drum spacer collars (see my Avatar) to beef up the developing unit I can send them to you. I have the eventual necessary seals as well. You can take the spiral mixing roller out of a Di-350/351 unit in case the ATDC wiper is worn. This applies to the other mixing rollers, gears, bushings and mag roller itself as well. We rebuild our Bizhub 350 series Image Units by cannibalizing not any more needed used Image Units of the Di-XXX series which are still in good condition.
It has been my observation that the problems with the collars or rollers wearing in the dev units started when the BH250/350 series started. You can actually feel the difference in the developer with your fingers. All this crap from Konica about getting dev under the mylars is just that, crap. The increased wear is due to the characteristics of the dev. I think you would be going down a risky path by switching drums & dev.
Incidentally, the 2510/3510 would have to have been one of my favorite copiers. We had virtually had no problems with these copiers at all. As per usual, Konica fixed the things that didn't need fixing on the next series and effectively went backwards.
I was of the understanding that DV110 and DV310 are the same except for the fact that there is 200g in DV110 and 300g in DV310. The drums are interchangable and that usually means that the compostion of the dev is the same. I have used the same drum to rebuild image units all the the way from the Di251 up to the BH350. Therefore, to me that means the dev is the same. I could be wrong though.