Disco 1 200tdi with a Euro 4 catalytic converter

I have a 1992 Discovery 1 200TDI with a boost pin and boost ring. I love the car, but I really hate the smell of its exhaust fumes. I know it might sound crazy to some of you, but I'm considering installing a universal Euro 4 catalytic converter. Has anyone ever tried this? What could the consequences be? Can I expect the fumes to be any better? I suppose so...

If you can smell the exhaust fumes inside the vehicle while driving you have a big and dangerous problem.
Is your tail pipe in the original location?
Fitting a cat might change the smell from your exhaust but you're still breathing in carbon monoxide.
I'd fix your problem in safer ways before thinking a cat will fix it.