i have been slowly doing mine mate, best bets are to do the following all prices very depending where you buy them:
1. PD160 Intake Hose & Adapter - £70 Roughly
2. K&N or Green Cotton Panel Filter - £45
3. Forge 007 Diverter Valve - £90
4. Full Miltek Cat-Back exhaust system - £
290 Non Resonated
5. Custom Code Remap - £312.55
If you get all these upgrades you can easily see 200BHP - 210BHP out of that engine phase 1
Then all you need to do to get to Phase 2 is
1. Sports Cat - £350
2. Another Custom Code Remap £312.55 (40% Discount for upgrading)
From this you will see between 230BHP - 240BHP
Hope this gives you a bit of guidance