not sure bout that i think it s nearly the same but if you want cheapest go for the 1.8td cause it s a factory turbocharged engine so it has lower compresion cause if you fit a turbo to the 1.6 you need to buy turbo intercooler manifolds and then fit them to the 1.6 (unless the 1.8 and 1.6 utilise the same manifolds but i don t know). anyway if you fit the turbo to a non turbo engine you ll have a faster engine due to higher compression but you ll risk blowing it if you exagerate :P cheers and good luck

btw thanks