All of the hush kits that I've seen (FedEx, Quiet Wing and Valsan) got rid of flaps 40 in the mid 90s to meet Stage III noise standards on the approach. Less sheet metal in the breeze=less thrust to maintain glideslope=less noise.
Our VSIs only went to 6000 fpm and it took very little effort to peg them. I did one gear down ferry and when it was time to start down, it worked out to less than one mile forward per every thousand feet down v. the standard three miles per thousand.