Another vote for AGU with uprated turbo. Coil packs never really go, plus throttle cable means less to go wrong. k03s is yours for £250, then about £80 for the new bolts and gaskets. £250 for fitting unless you're handy with spanners. That'll get you well over 200bhp with a re-map. Then FMIC, better air filter. You're also definitely going to have to upgrade the exhaust, something of the 3" variety.