Try the fusion EN-CM525 around £35-40 with 180 watts to play with they also have twop amps to make the sound crisp and with tweeters aswell for the highs. I have a mk 6 escort and have put these in, dont know if the mk 7 van is the same though?? anyway heres what i did..
You will need to do some mods to the speaker units alreday exisitng, take out the old speaker units, removal of the door card is needed to get access, remover the speaker unit and take the speakers out of the casing they are in, clips on the back and they are also glued in, then you will have to put the new speakers in by screwing them to the existing case with out using the case you will need to buy an adaptor kit otherwise the speakers will stop the windows from opening- this happened to me..lol
its a tight squeeze but this means no modding to the actual car once this has been done you need to drill a hole to fit in the tweeters, they fit in the outline hole already in the unit and they just pop in, now you have to wire this all up i have put the amps in the draw at the bottom of the door, drill a hole through the door card to get the wirs through. and then replace the door card and jobs a gooden. make sure you tape all the excess wire to the inside of the door card as putting it into the void will get in the way of the window and may cut the wirtes. hope all goes well and will be hearing you soon