Sub/Speaker upgrade the Lazy way

[T400]

Hi

I have the standard speaker setup in my 56 Z4
I have sat nav
cd changer
and the
mfsw

im looking to upgrade the speakers / add a sub to give it some oooomph

Ive read most of the posts about a DIY install and Im afraid its beyond me.

Is there anywhere/anyone that you could reccomend to carry out the task for me.

I know it seems a cop out, but id rather pay someone to do it than haver me fudge it badly

[RustyZ4]

Where are you from?

i know a good guy in Kent

[T400]

Im in the midlands area

preferably an actual company ( so I can tell em off if its wrong)
or
someone who has done something similar on their/ a/ z4 before..

cheers dudes