To the best of my knowledge, this page accurately describes the procedure that I followed to install a 22mm Neuspeed rear swaybar on my 2000 A4 1.8TQ. Although the bar fits '96-'01 A4's and S4's, I cannot confirm that this procedure will work for your car.
Use these instructions at your own risk.

• Hydraulic floor jack and two jack stands. Optionally, three hockey pucks for cushioning the jack saddles.
• Tools for removing wheel.
• WD40 or some other lubricant for loosening fasteners.
• 5mm hex key for end link allen bolts. A hex key ratchet (socket) wrench would be even better.
• 17mm open end wrench for end link hex nuts.
• Torque wrench with 17mm and 13mm attachments.
• Two 13mm open end wrenches for bushing and subframe brackets. Or even better, one 13mm open end wrench and one 13mm ratchet wrench with 2" extension.
• Neuspeed swaybar kit including:
  • Two subframe support brackets
  • Four M8 washers
  • Eight M8x1.25x25mm hex bolts (preferably four flanged and four regular)
  • Eight M8x1.25 hex nuts (preferably nyloc)
  • Two M10x1.50 hex nuts (preferably nyloc)
  • Two 22mm polyurethane bushings with brackets
  • 1/4 ounce bushing grease

 

1. Lift the rear of the car and remove wheels.

Left (driver) side rear jack location Set the emergency brake. Loosen the lug nuts on both rear wheels with a lug wrench or breaker bar (not a torque wrench). Place blocks in front of the front wheels. Lift one side of the car with the floor jack and slide a jack stand under a solid location on the chassis. Do the same on the other side. Floor jack under the cross member lends extra support For extra support, place the hydraulic jack under a solid location down the centre axis of the car. The jack should just touch the chassis. The floor jack should not bear much weight. That's the jack stands' job. Remove both rear wheels.

2. Detach swaybar from end links.

Left (driver) side end link The ends of the swaybar are attached to plastic end links located just behind the brake rotors. The hex nuts are torqued (74 ftlb) on fairly tight and can be quite difficult to remove. Spray some WD40 on the nuts (don't get any on the brake!) and allow them to soak for a few minutes. Hold the end of the bolt with a 5mm hex key (or hex key ratchet) and use a 17mm open end wrench to remove the nut. Apply WD40 as needed. Right side end link

3. Detach swaybar (bushings) from subframe.

Right side bushing Remove the four (two per bushing) 13mm hex nuts/bolts holding the bushings to the subframe. The right (passenger) side is particularly difficult to reach because of the gas tank. The easiest way is to hold the bolt head with an open end wrench and remove the nut using an extended ratchet as shown above.

4. Remove the swaybar.

Stock vs. Neuspeed The exhaust prevents the swaybar from dropping straight off the car after all the attachments are removed. Carefully work the bar around and away from the exhaust.

5. Install subframe support brackets.

Right side bracket The reinforcement brackets attach to the subframe just behind where the bushings should be. There are strategically located holes on the subframe for mounting the bracket. Left side subframe. No drilling or welding required! Attach the wide section of the bracket to the subframe first, but do not tighten the bolts. The bolts and washers should go on the outside (visible side of the subframe) and the nuts on the inside. Use a 13mm open end wrench to hold the nut on the inside while tightening the bolt on the outside with a ratchet. Loosely attach both brackets to each side of the subframe. Loosely attach the wide section of the bracket

6. Grease the bushings.

Energy Suspension bushing grease Coat the inside of both bushings with the supplied bushing grease. If you purchased the swaybar secondhand like I did, and don't have the original grease package, you can use Energy Suspension Formula 5 Prelube (#9-11101). It is specially formulated for use with polyurethane bushings. Slip the bushings onto the swaybar on the middle section just before the bend.

7. Attach swaybar to subframe.

Left side bracket and bushing. Slide the bar over the exhaust and line up the bushings with the subframe mounting holes. Sandwich the subframe between the bushing and reinforcement bracket. You may need to slide the reinforcement bracket around to get the holes in the bracket to line up with the holes on the subframe (this is why you should not tighten the bolts during step #5). Tighten the subframe bolts with 18ftlb of torque on both sides of the car. Do not overtighten the bolts on the bushing as it could bind the bushing and cause squeaking.

8. Attach swaybar to endlinks.

Set stiffness using the end link mounting holes The bar's stiffness is determined by the mounting holes at the end of the bar. The shorter the bar, the harder it is for it to twist during rear suspension travel. Attaching the bar using the inner hole (toward the middle of the bar) effectively shortens the bar, making it harder to twist (ie, stiffer). Conversely, mounting the bar using the outer holes (toward the end of the bar) lengthens the bar, making it easier to twist (ie, softer). Neuspeed suggests mounting the bar with the soft setting at one end and the hard setting at the other to achieve medium stiffness. This sounds a bit weird to me, so I just mounted the bar at soft on both ends. Clean off any WD40 residue from the end link bolts before threading the nuts. Tighten the endlink nuts with 74ftlb of torque. Finish off by remounting the wheels, lowering the car, and torquing the wheel lugs to 89 ftlb.