Because it will allow more pressure at the rack, highspeed driving will be dangerous. Let me explain. I decided to take a course on driving and racing techniques. It was very helpful and I recommend it to everyone. While doing some of the manouvers, the steering seemed to lockup under hard turning. It seems the speed sensitive valving in the steering pump is based on engine RPMs, not actual speed! You can witness this while sitting still. Start the car, put it in netural (or leave it in park) and turn the wheel back and forth quickly. It should turn pretty easily. Now slowly increase engine RPMs while turning the wheels from side to side. On the 2.0L DOHCs, the steering will become increasingly stiff at approx. 3500-4000 RPMs. The higher the RPMs, the stiffer the steering becomes. Now as for the racing part, most of the races around my area are done in parking lots with cones. Usually you don't need to get out of first or second gear because there aren't any long straights. This really causes a problem when you have to steer quickly because the engine is usually ABOVE the 3500-4000 RPMs. The fix i have is probably not the best solution, but it works. I highly recommend that you have the service manuals before you do the modification. Here's how the pump works as far as i know:

The pump has a pressure valve thats pressed up against the high pressure line connector via a strong spring. During low RPM's the fluid passes over top of this valve and into the high pressure line. When the RPM's increase, so does the pressure. When the pressure reaches a certain pressure (approx 1277 psi) the pressure valve compresses the spring. With the valve pushed down, there is a chamber which leads to the non-pressure side of the pump. This allows the pressure to remain basically constant, problem is, the fluid now is also pulling down on the valve(fluid flows from pressure side, to non-pressure side, back through the pump in a circular fashion), so the pressure at the rack drops, resulting in a loss of powersteering help (the steering wheel will be HARD to turn quickly). So that leaves us with 2 ways (possibly more) to increase the high RPM pressure retention. 1, get a larger valve that will decrease the size of the low pressure chamber opening, or 2, increase the spring rate so it's harder to move the valve. I opted for 2 because the valve has some intricate parts and i don't have a lathe. Here's how i did it..

1. Get the service manual, a couple of shop rags (it gets kinda messy), something to suck the fluid out of the chamber into, some ratchets and needle nosed pliers (small ones), a tray to put some parts in so they don't get dirty/lost, some DEXTRON II (2 not 3) ATF, a couple of new clean washers about 13-14mm in diameter, and about 45 minutes of spare time.

2. Remove the coolant overflow tank (just lift it off, no bolts hold it on) and disconnect the wire. Set this aside.

3. Place a rag over the airconditioning pump so that fluid doesn't run all over it and into it.

4. Using a ratchet, take off the high pressure line, then take off the suction hose and plug it (i used a 3/8" ratchet extension to plug it)

5. Take the connector off the top of the pump (the one that the highpressure line connects to.) Be careful when taking this off because there is a spring load against it.

6. You may want to take the pump off the car, i did it with it on the car, it's not necessary to remove it.

7. suck all the fluid out of the top of the pump that you can get. you should see the top of the pressure valve. (i used a hand primer from a snowmobile to suck out the fluid.. worked great)

8. with a pair of small needlenosed pliers, take the valve out of the cylinder (it may take some patience.. if it's not coming out press it down a bunch of times to get some of the fluid out beneath it)

9. when you have it out, remove the spring and suck out the remaining fluid from the chamber/cylinder.

10. compare the size of the washers to the size of the spring, you want the washers to sit on the bottom of the cylinder with the spring pressing them down holding them, you don't want em floating into the pump. ;-))

11. Look into the cylinder. At the bottom there is a relief a couple of mm from the bottom of the cylinder (small hole about 2mm across). you don't want washers covering up this hole! (if you do you will get a fluid lock and the valve WON'T move down, causing excess pressure build up, resulting in blown seals on the steering rack... see what a 5 cent washer will do to ya!)

12. By varying the thickness of the washers (or stacking them) you are increasing the spring tension somewhat and you are reducing the amount that the valve can travel. If you can find a spring that works that has a higher tension, let me know.

13. Put it all back together, remember to put some fluid into the pump before bolting on the highpressure line, this reduces the amount of bleeding your going to have to do. Also add fluid to the reservoir and check it to make sure you have the proper amount (you;ll need approx 40mL of fluid, depending on how much you spilt.)

14. Take it for a road test. Be extra cautious on the highway as the increased pressure will allow you to turn the wheel easier. Also I take no resposibility if you blow the seals in your steering rack, pump, or anything else for that matter.