I know this has come up in related threads, which I have read, but I have a different enough twist that I wanted to ask for specific opinions, since I already own one and am considering trading for another.

I already have a red 2005 Dinan S1 MCS cabrio with 30K miles (installed by SanFran Mini when sold new). I found a black 2006 JCW MCS cabrio with 13000 miles on it which I can probably get for $3k-4k plus tax/etc plus my Dinan. I've got Dinan centers close to my house but never need the Dinan stuff serviced so take it to my german-car mechanic anyway. So service issues (and blowing up engines) are not issues I want to get into. It comes down to a year newer car and Dinan S1 vs JCW factory kit although I prefer red to black and my Dinan has the chrono pack, which I prefer).

I was considering adding Alta to whichever one I end up with but it's not clear if they already have a peformance pully in the S1/JCW.

 

Not sure what the Dinan S1 package is comprised of, but I don't think it's as extensive as the JCW package. Maybe the S3 package is comparable. Anyway, since you like your color and chrono better, I'd say keep your car. For the 3k difference, if you really want to burn a whole in your pocket, you could extract some serious power from a pulley, cam, and head.

My 2 cents

 

Keep the 2005 MCS and add $3K-$4K worth of engine and suspension mods.
Go talk to Dinan about what can be done for $4K.

 

http://www.dinancars.com/store/produ...cat=763&page=1

The Dinan S1-MINI Cooper S features the full compliment of Dinan intake and exhaust enhancements, bumping horsepower to 182 @ 7000 rpm, without any increase in boost pressure! The S1 intake system takes full advantage of the high pressure area in front of the windshield, force feeding air into the larger volume air box and free flow filter for maximum power gains. Stage 3 Engine Software is included, providing the appropriate air/fuel ratios and ignition timing for optimum performance and drivability. The software also provides a 300 rpm increase in the rev-limiter, allowing you to carry more speed in each gear as well as optimizing shift points. The Free Flow Exhaust reduces back pressure from 2.5 to only .7 psi, enabling exhaust gasses to pass through the twin 3-inch polished stainless tips as efficiently as possible, as well as producing a roarty exhaust note that is sure to please the MINI enthusiast. The system also includes the beautiful and very effective aluminum and carbon fiber strut tower brace for improved chassis rigidity and a look that screams high performance.

 

That's a good start, you've got a good air intake and exhaust. I'd still keep the Dinan and spend the money on a good head, pulley and cam, and a new custom dyno tune to really pull it all together. Good luck.