I have a 2000 Si and have driven the 2006 Si. By far the new SI superior by all means. It has 37 more HP and approxamately 28 more TQLB versus the (99-00 SI) B16A2 160hp/111tqlb.However the new SI is heavier but its close ratio 6 speed transaxle and Helical LSD make up for it.I persoanlly am a fan of the Double WIshbone Multilink Suspension over the new MacPherson Strut Suspension thats on the new Si. That I beleive is about the ONLY downside to the 06 Si.Besides you can get navigation as a standard and the optional Brembo Brake package for a little more.The interior is VERY nice. The steering wheel was not a eye pleaser in the pictures but is much better when you are behind it. The Gear shift is in a awesome location. Not like the 02-05 Si with thier failed rally inspired dash mounted shifter. The new shifter is located similar to the typical location but quite close to the steering wheel making it very easy to make fast shifts and being able to regrab the steering wheel.Now the best part in my opinion is how great the 06 Si shifts. A few words can only explain this! SUPER SMOOTH and EVER GEAR just about matches the SPEED & RPM where it would be to provide optimal performance. Also the Helical LSD + 215 tires just grabs, hands down. Traction is NO LONGER a issue unlike the open differential that came in the 99-00 Si. Persoanally a set of 225's will make this car perform even better.Last but not least the K20Z3 with its (SAE rated) 197 bhp & 139 tqlb are very usuable dispite the wieght of the 06 Si (2877lbs).So is the 2006 Honda Civic Si worth the estimated $20,000-$22,500. In my opinion, yes. No it doesnt have a turbo but it did dust off the turbocharged 2006 VW GTi in Road & Track Magazine's test. Not the mention the GTi was even more exspensive.As for the SRT4. It has respecable power but all you get is cheap plastic and a turbo. It doesnt even hold its value.The 2006 Honda Civic Si will also hold its resale value better than pretty much ever car in "its" class.