IMO, TS current engine is what?
if wira 1.5 carb then just upgrade to MMC injection.. from there there's a lot of performance part for it
if wira 1.5 injection SIEMENS then its kinda troublesome, try to change to MMC injection
if wira 1.6/1.8 single cam injection, its a lot better.. just modified the current engine where there still a lot of performance parts
if wira 1.8 DOHC its the best engine either to upgrade turbo engine and sell of the engine to get better performance or just upgrade the engine.. but extra torque require a lot of modification which the cost could be sky rocket, either words its high maintenance..

i did try to mod wira 1.6 single cam.. its quite good too, just minor mod like piggyback, better outflow n inflow, racing clutch, racing disc n racing brake pad, higher compression ratio etc.. i can get 0-100km/h in 8s flat..
its not major mod eg block cutting and balancing, racing cam, racing valve, racing valve spring, stand alone ECU etc.. even the head also almost completely stock..

so imagine for those turbo engine.. huhu