2007 s-max speaker upgrade recommendations for £200-£250?

[Tetsugaku]

 

Hi all - I picked up an old s-max with plenty of cosmetic wear but structurally sound the other day to use for camping and shifting things about. 

I’ve already upgraded the head unit to a Sony XAV-AX100 because I wanted Apple CarPlay, but it turns out the factory Speakers are, shocker, a bit crap. 

I know it’s a lot of money to spend on a car that won’t last forever but I can always take it all out and put it in the replacement in a few years!

I can install myself no problem, but do need to know all the bits I need including brackets and wiring. Budget isn’t set in stone but I’d rather not go higher. 

Any recommendations on what to buy? I don’t want to go to Halfords and get some crap that doesn’t make it sound any better!