A friend who is involved in motorsport just bought one for going to the shops in. He also does the odd track day with it, here's his spec. It might give you some ideas.
GTT Tuning Engine Upgrade 230 BHP
Garrett Big Turbo Conversion
GTT Induction System
GTT Tuning Chip Module
Bilstein PSS Fully Adjustable Coilovers
Goodridge Braided Lines all round
Super Blue Racing Brake Fluid
Miltek Lightweight Exhaust (Turbo Back) with 200 Cell Cats
Upgraded Abarth Stubby Aerial
Custom Cages BN Colour Coded Rear Roll Cage
Interior Rear Carpet Professionally Re-Trimmed
Run on Mobil 1 Extended Life Oil - 10/60W
NGK Laser Iridium Spark Plugs