Genuine OE Audi C5 Strut Tower Cross Brace Part Number 4B0-805-645. Brace is in used but as new working condition, good cosmetic condition.
Shortened and re-drilled inboard 25mm on either end of cross member, this is a direct bolt-on stiffener for the B5/5.5's front suspension geometry. I can do the required mod on my bench and send it to you ready to install, or send it to you as-is for you to tinker with directly.
Once modded, this is at most a 20 minute install. Loosen your battery clamp, remove two of three strut tower bolts from either side, slide the bar between battery and firewall, under the brake booster and A/C lines, loosely install the end brackets with strut tower bolts, fasten cross member to brackets with supplied hardware, tighten bracket bolts and cross member fasteners, and tighten your battery clamp. Now go drive it like you stole it.
$75 plus shipping for brackets and hardware with modded cross member, $75 including shipping (lower 48) for brackets and hardware with as-is cross member.