The easiest and cheapest way to get to that power level with the supporting mods is actually quite easy and accessible.
- get injectors and fuel pump tested otherwise you might limb mode, if they need refurbishing, greg got a guy.
- buy the 1752 turbo from xman turbos part number: 7607441752 (£500)
- gravity performance st225 highflow intercooler (£170)
- jspperformance intercooler silicon hose kit ebay part number 155104095647 (£151) (dont use oem boost pipes they like to rip past 2bar boost, or go for bestoke metal boost pipes if cheaper)
- 2.5 inch stainless steel catback with twin exit (£500-600) @ rjperformance in Birmingham or Custom chrome in coventry about 90 miles from bristol
- map can be custom but i personally recommend hdi tuning for price and performance because they mainly focuses on psa cars. (£200 online service map for the stage 3 1752 turbo upgrade, which can produce 210 to 220 bhp depending on engine health)
- if you go for hdi tuning you can purchase a kess v2 clone and map it yourself in 5-10 minutes for £60 ( i done it too for my stage 2)
- please also do suspension mods
Hope this helps you out