Quick couple of questions re: import, licenses and mopeds

Hello, I am looking to move over long term over the next year or so. I have a couple of questions...
Firstly I have a 2003 UK mercedes diesel, I have owned it more then 6 months, what is it likely to cost to bring this in and legalise it? Do I need new headlamps or do the european light deflecting stickers count?
Also am I going to have to give up my UK licence and get a spanish one? And finally I was thinking of buying a 125cc moped over there, can I drive that on a UK car licence or do I need to do my bike test. Thanks in advance for any help :)

You will have to change the headlamps, stickers are no longer allowed. Don't get a Spanish licence. You can legally use your UK one unless you become a resident. (Don't do that, the gains are minimal the downside is huge) Good luck with your move and be sure to ask plenty of people before you commit to entering the system here.