I want to ask you exsperianced engineers before i go dissasembling new engines... I Have 2 bachman spectrum DCC ready 4-6-0's I'd like to know what model decoder i should get, am I looking for a DH123D, DH123P, DH123PS, DH163,P, PS, IP I'm totaly lost if have read the discription of each on the Digitrax website but I can't tell one from the other. I belive they have an internal plug with jumpers ready for a decoder and harness. I'd like to stick to the Digitrax brand name as that is what my system unless you recomend another brand of decoders. I allso have 2 bachman spectrum 2-8-0's DCC equiped should I change them over to Digitrax decoders, what type of connection is inside of them are they Plug or Solder installations?