Alright Dez,
A bit of background on the Mk1, practically the same chassis as a Fiat Strada (top model was a 2.0 twin cam on twin 40's, same engine as the Lancia delta Integrale (different rear end on this chassis as it was a 4x4) and Fiat coupe 16v turbo)) one of my future plans.
Parts are like chickens teeth, Auction sites are definitely worth looking at, I'll list some mods I've done or am doing...
Front wishbones, get new ones from an auction site, dont pay more than £25ish for 2, make sure you get the right size for the tie bar 19mm I think (measure it!) then buy a set of Fiat Strada front wishbone bushes, these are the ones that mount the wishbone to the chassis, gotta cut or press the originals out first.
Rear wishbones, well this is something I am working on at the moment, looks like all of the bushes are the same and there is no listing from Powerflex for the
Ibiza or Strada so customs/universals is the way to go, I think I have found the ones, I'll update this post when I get them. Superflex could make customs which I may look into.
Suspension, you can get a cheapish kit, Gmax do one for about £260 with front springs 30mm drop, Koni supply shocks all round and you can get your originals rebuilt. other spring options are Jamex, they also did a full kit which is the one I have on mine but changed springs for Spax, the Jamex kit also came with lowering blocks for the rear, got to be careful with lowering the rear end due to the brake compensating valve, look at brakes below, Gaz suspension I think will make up a set of coilovers from an original set of shcoks by rebuilding them and threading the bodies but you would have to call them for a price, if you do this seriously think about bracing the back end when you remove the rear leaf spring.
Induction, I'm running a Green cotton induction kit, this is angled to curve around the fuel rail and sit in the dip of the inlet manifold, you can just get a universal one and re-route the pipework to where you want it, after all theres loads of room under there (take the spacesaver out from under the bonnet).
Exhaust, I working on this at the mo too, the original was a 4-2-1 but where it goes into one its 4-2-box-1 to a centre to a back box, I've changed the downpipe already to that from a carb model which does away with the first box and looks totally standard so currently goes 4-very long 2-mid box-rear box, I have been running a Remus back box for a while now (although the car has been garaged for years and the back box has only seen around 300 miles) I have recently aquired an ANSA race manifold, downpipe and mid section which I have wrapped in glass fibre exhaust wrap. Supersprint also did back boxes a few years ago, may still be able to get them, universals could also be the way to go, I also saw a porsche boxer exhaust modified and fitted under the standard bumper with a centre exit.
Brakes, a few solutions with this, the front end is quite adequate as you can lock the front up very easy even with everything set up properly as it has drums on the back, I originally replaced the drums and shoes and cylinders with EBC equivelant but this made no difference, even with Goodridge braided lines, now I'm in the middle of a conversion, I have a brand new pair of Fiat Uno Turbo 1.4ie rear calipers, EBC pads & EBC discs, pads & discs relatively cheap @ £12 for blackstuff pads & £25 std EBC discs, calipers I pulled off an Uno Turbo I bought from an auction site, you also need Uno Turbo rear bearings & hubs as these have a larger offset to compensate for the discs and calipers, if you do go down this route, you also need the mounting brackets from an Uno or if you get really stuck then I may be able to provide them as I could get them made up, also the calipers have to be mounted upside down to enable the handbrake cable to be mounted correctly, again more details to follow or upon request. Front end you can go down a couple of routes, theres the Lanci Delta intergrale 284mm discs & calipers same as the Fiat Coupe 16v turbo, I'm going down the route of the Fiat Coupe 20v turbo with Brembo 4 pot's & 305mm diameter 28mm thick discs, mocking up a bracket to mount the caliper at the mo, again, if it's a route anyone would like to go down I may be able to provide brackets if I get them made up, with this kind of setup or even just doing the rear conversion the master cylinder has to be uprated from the original 20.5mm to at least a 22mm (which I think you can get from a Mk1 Golf GTI 16v Bosch unit, I'll let you know when I get to that hurdle).
Strut braces, Weichers do a strut brace for the front end only but they also do a roll cage which may well be worth getting if you go nuts with your car especially if you do the rear coilover conversion and a rear anti roll bar is a must unless you compensate by leaving the rear leaf in and an anti roll bar is again a custom job but again, I have some info on this.
If you or anyone else has any interest I'll post more info, if theres enough interest then Mr Moderator please make it a sticky or add the info to the relevant area.