both can be done mate but the dash is expsensive its somthing like £90+
steering wheel controls can be done for about £40 you need to check see what work with kenwood for example auto leads dont work with pioneer if you get me.....
but any auido will stock like halfords etc....
you'l need 2x wires
1x main wire to connect to car
1x patch lead for your manufactuer of headunit