I think replacing the whole panel would be the best approach. However, If this replacement (guts) are UL approved and have been proven safe, then why not?
I used to be a Square D fanatic. I have one in my own home. Would'nt settle for anything less.
But, I now am open to others such as Cutler Hammer, GE, Gould ect....
Square D panels only accept Square D breakers. And I like to know that I will be more than 90% sure that I have a breaker that will fit, with me in the middle of the night.
Now, I do not know anything about their Homeline panels. I think thats what they are called.