Apparently the OP created two threads on the same topic. Here's what I had posted to the other thread, I suggest the other thread be closed:
The 6603 is a 10 speed derailer. This matters because the width of the cage on a front derailer changes to match the width of the chain, which is thinner for 10 speed.
Any 9 speed triple front derailer should work fine. The 6603 might work if you are willing to bend the cage a little to give more clearance at the points where it is needed. An 8 speed will work ok as well if you bend the cage to be tighter where it is needed.
A bigger factor is the number of teeth difference between the largest two chainrings vs the cage design of the front derailer. The 6500 and earlier series are made for a 10-11 tooth difference, in other words 52-42 or 53-42. 6600 and newer derailers are made for a 14 tooth difference, in other words 53-39. If you use a front derailer for a chainring difference it is not designed for, it will still work, but not nearly as well.
Rear derailers, on the other hand, don't care how many speeds you have as long as the cable pull is the same. Most long cage derailers will work just fine, except for a few newer exceptions - I think shimano mountain 10 speed is different, and others can probably contribute more accurate info. But any older xt, xtr, etc. will be fine with any speed shifters.