Dichroic Heads are needed for Colour but will do B&W as well.
All the other alternatives are mainly aimed mainly at Black and White.
It is worth thinking long and hard about what you might want to do with your Enlarger – what film sizes & what print sizes
Enlargers are really simple devices and there is little to go wrong with them, so the age of an Enlarger is fairly insignificant.
It is worth investing in a decent enlarging lens – all your work goes through this one lens.
Most people start printing with Black and White before moving on to colour.
Getting the basics right with B&W is fairly straight forward and doesn’t need a huge investment in equipment.
To print in Colour needs rather more specialised equipment for print processing and needs to be done in complete darkness.
Don’t be put off; its great fun and great results can be obtained in surprisingly small spaces with fairly simple kit.