Hey, gearheads! We're excited to share the results of our latest project: the 2005 Audi S4 with a 4.2L naturally aspirated V8. This beauty came to us stock, and we've given it a modest yet effective performance upgrade. Here's a rundown of what we did and the impressive gains we've achieved. What We Did: Engine Freshen Up: Ensured the heart of the beast is running at its best. Muffler Upgrade: Enhanced the exhaust flow for better performance and sound. Custom Dyno Tune: Fine-