Start with the Pulley and then decide how much faster you want to go.
http://www.waymotorworks.com/home.php?cat=325

 

Might want to ask them directly, but I have been exposed to a couple of installs of the kit and all of them required further modifications to work properly. I personally would not do a twincharge/twurbo kit if one of the main concerns is reliability. Even more so with all the other proven methods of modifying the MINI.

Good luck, and remember that your first mod should be the one that puts the most smiles on your face.

 

Reduction Pully! I have Alta's 17% & new belt, Irid spark Plugs. I still get 39 Mpg highway as long as I don't horse around with the SC, and get 34 mpg combined in a tank. And I would be careful with any exhaust stuff. Some cat back kits raise decible levels inside the vehicle to the point of being annoying and untollerable for lengthly trips and for merely 5-8 wheel horse power, not a real good trade off.

 

Thats why you get a cabrio- no drone!

 

Surprise a Vette in the straights and then get back to us!

 

Driving school first - the mini is way different from your other two cars. It certainly won't embarrass either of them unless you have a good driving school... even then you're limited to tight twisty courses and autoX unless you ALSO have some bank!

That said,
1. CAI
2. Pulley
3. Exhaust

Seems the most cost effective way to go, should cost a grand or so and get you another 20-40hp. Beyond that you're likely sacrificing durability and spending lotsa cubic dollars. Alta is great, there are other great products out there but Alta seems fairly cost-effective. Also check the marketplace on this bb - and check the forums for more advice... (search is your friend...)