needs some ideas on aero mods for our mk1 focus, we will be making a rear diffuser, front dam/splitter and trying to flat bottom as much of the car as poss, any comments would be great..

 

If you want to go the whole hog do a bit of arch work and make cutaway wings to get rid of the pressure build up inside the arches. Could be worth looking at a modded wrc bumper and wing combo.

 

diffuser looks cool, and will stop parachute effect of rear bumper, but I think the car's ride height is way to high for diffuser to create any downforce

 

There is a very slim window for a diffuser to work as well angle wise as porkie said the car needs to be lower. If you get low enough you could take advantage of ground effects too.

 

just to add this is not our car just some idea,s, do you think that a rear wing will be of better benefit over flat bottom/rear diff? plus we need to sort out front splitter/dam as a standard focus front bumper is way to high..