I'm on a budget but would like a cd player with mp3 capability, a
powerful amplifier (100 watts or more) and a radio tuner. Cassette deck
is not important but might be useful. Having 1 remote to do everything
is a plus.

I do not have a lot of space either so...

What about buying a mini system (Panasonic, Sony etc) for around £150
and putting some better speakers (£150 worth - mission, bowers &
wilkins etc) to this sytem?

For £300 would this sound much better than just the standard £150
mini system?