The way I see it is, if someone is prepared to pump as much money into a Cosworth as the top spec Evo's and Scoobs, then the Cosworth will be up there with them. Just no one is prepared to spend.
The suspension has to be one of the most outdated parts of the car that needs massively improving on to start with. Thats a fair few quid up the shitter......
Then for the 4x4 cars you need something like an FFD dogger and diffs the size of my cock to take the power. Again, mega money to someone trying to run a Cossie on 18 grand a year whilst paying a mortgage....