In that case id say go for the usual stage 1 things
- Drop in filter
Factory direct K&N replacement air filters, air intakes, oil filters & cabin filters. KNFilters.com - the official site for performance filtration products.
www.knfilters.com
- Stage 1+ tune for the fuel grade you most have access to 85-100HP gain
We're excited to announce our Engine Control Unit (ECU) Upgrades are now available for the Audi S4, S5, and SQ5 3.0T EA829 engine with the Bosch MG1 ECU! Expect massive gains with up to 411-491 HP with 551-629 FT-LBS of torque on tap, depending on octane, from this simple software upgrade.
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Exhaust

- not much to be had for under $2000, you could enquire with a tuner shop about freeing up the factory exhaust by replacing centre section with a free flow resonator, and perhaps removing some pre resonators. TBHthe stock exhaust should be fine for a stage 1 tune. 85-100HP with extra torque will certainly be noticeable. Exhaust may give you an extra 10HP but unless you you get something off the shelf like Milltek, the sound it will make is unknown (may have drone, may make no difference)..
If you've got some $$$ left over after filter and tune perhaps some nice tyres for added grip ?