here is your franchise tag costs
QB: $10.73
WR: $7.85
OL: $7.46
RB: $6.54
TE: $4.53
CB: $9.47
DE: $8.88
LB: $8.07
DT: $6.36
S: $4.34
This can give you a basis for what the costs are in a position by position basis. As for the costs in a 4/3 vs a 3/4 defense those figures would lie if they were to be posted. There are 2 sides to a football team you have to remember that. There are coaches that are offensive minded that subscribe to a 3/4 and ones that are offensive minded that subscribe to a 4/3. Their money however would go to the offensive side of the ball. I for one think this is a terrible idea because if I am an offensive guru I would put all my money on defense and believe in my talent to make the offense work with less talent, but that is not the way the world seems to work. There are also defensive coaches that believe one way or another. They will put more money on the defensive side of the ball. A better question would be where would most of the money be spent in a 3/4 vs a 4/3? To answer your question simplistically parcells likes big bodies on the d-line. Obviously he wants all stars there, but a big body will do. A franchise tag cost isn't what he is after here. He loves his LBs big, smart, and fast. These are harder to come by and will come in closer to the franchise tag cost if done the way he wants. (yeah there is getting them in the draft cheaper etc... I am just saying in general if all were free agents). He loves his corners tough and aggressive, basically being able to blitz and make the big hit. Since interception/shutdown type corners are harder to come by than big hit/blitzing type corners, we can spend a lot less on corners than the franchise tag calls for. On the flip side he loves his safeties to be able to cover huge tracks of land to be able to cover for the corners lack of ball hawk ability so to speak so that will come in closer to the franchise tag cost. Of the 5 top paying positions in the NFL on defense, the 3/4 really requires the 3rd and 5th spot as opposed to the 1st,2nd, and 4th spots. This makes the 3/4 arguably more efficient as far as cost goes.