The tdi is much heavier than the petrol, plus I would imagine the whole suspension set-up would be different between the the golf and toledo, as they are different wheelbases, and will no doubt have far different spring loadings.
A mate once took a set of springs off a 1.4 escort and fitted to a 1.8 of the same year, and they were useless.
I would always buy the correct parts for the car, especially with something like springs,