I would look out for a focus rs manifold, a t25 (can both be had cheap) use or make a downpipe from a focus rs, make your own oil feed and return and water pipes (easy enough) and make your own boost pipes. The ignition map will be safe enough as std, The use of a mappable fifth injector will see 170-180 bhp on a std engine for around £500-800, you will pos need a walbro fuel pump, and i would also recomend wideband to set up the fifth injector.