If you are looking at the Alpine 9871R unit (which I can't find for
less
than £89) then I would recommend looking at a Kenwood KDCW6537U. Good
quality unit with decent USB input, it may be at the top end of your
budget but in my opinion is worth it.

http://www.incarexpress.co.uk/view_p...rtno=KDCW6537U

Speaker wise Sony are ok for a general replacement of the OE stuff.
Much the same with all of the speakers in that £20-£35 price bracket.
I would have the JBL over the Sony.