The absolute furthest back I'd put the turbo is after the cat right around the flex pipe. Just under the intake manifold. Aerocharger did that with their Focus kit and did good numbers with decent spool up. The Porsche 944 turbo also had a similar setup with a long exhaust manifold with the turbo close to the intake. I don't know if there's enough room in the Cougar under there to squease the turbo in though.

2000 Rio Red I4 Cougar 200whp & 210wtq at 9psi 254whp & 276wtq with NX 35shot WRX TD04 Turbo, Cut Short Shifter, Strut Tower Bar, 17" ZN Wheels, Roush Springs, Starion Intercooler, NX 35 shot, HKS SS BOV, Full 3" exhaust,StreetFlight Chip