Re-upholstering seats

I was going to install the foam and covers I got from legenday, I sand blasted and repainted the frames, and when I went to install them, the instructions said "moderate to extreme modification to the seat foam is required". Due to that I took it all to an upholstry shop and he did a great job. Only cost me $300. It was worth it to me not to mess up the foam. If there was no modification required I would have tried it myself.