I just priced out a 335is and compared it with a 335i with the M package. The 335is costs $4000 more and includes the following options not available on the 335i: 1. Additional oil and water coolers 2. Performance tune (extra 20 hp; slightly more torque) 3. Sports exhaust system 4. Minor cosmetic items (black exhaust tips, black grill, no fog lights, distinctive badges) 5. Slightly different spoke pattern on the 18" wheels compared to M wheels. Frankly, I don't see $4000 in added value. A Dynan tune and heavy duty oil cooler would accomplish more for less. What am I missing?