I bought a genuine parts radio fitting kit off e bay £24 inc p&p.
Two radio mounts, two speakers and mounts, areial intructions and wiring.
Good kit, tryed to get the rear speaker kit but the price, £80.
Made my own speaker harness for a four speaker setup (the kit is only setup for 2)
Also fitted a nokia bluetooth hands free kit that works with the stereo front speakers.
Still trying to find somewhere to hide it though. works great.
I have had my 90 for many years but never fitted any sounds.
Quite pleased with myself.
Lots of fiddling.