Exhaust cats ?

Hi all, I have a 1990 3.9 non cat rrc and the exhaust is like a colander.
I can get a good second hand system cheap (as funds are very tight and wife would much rather a new hoover) but it has cats fitted, will this make any difference to the running of the rr or will it be ok to fit this without any problems ?

no as long as they arent blocked ,cut them out and relace with std pipe ,sell them to local scrappy get your money back