Firstly I am enjoying your game.
My major suggestion is that the suppliers need to have their attributes mixed up a bit to give each one a certain strength and weakness. Obviously the more expensive supplier should have more + than - but there is a clear need to mix it up a bit. As it stands certain suppliers are no brainers as every attribute is superior to others other than a small cost increase. As money is not tight in this game that becomes a non-issue anyway. Hence we have virtually everyone running the same supplier. Boring!
Maybe you are planning to mix it up wth the new design model but this area appears to present opportunity to further force the player into interesting comprimises.
Good luck.
Daryl