Don't know if they changed it but the mk5's had design flaws, they always rotted through the floor and along the sills (inner and outer) in the front foot wells and also the petrol filler holes would go from the inside out.

I remember having a scab on the filler hole on my mk5 and having a dig around and ended up with a gaping hole with nothing left round the filler neck same with the floor pan, once I'd removed all the rust I had a flinstone car.

That reminds me, when my car got shunted from behind from a mk4 Mondeo, the rear chassis legs had also rotten and just snapped under the strain

I'm glad chassis have improved since then.