If you thinking of going down the turbo route then a 2.0 blacktop would be a far better base to start with and you have more options also in that respect even with it in N/A form or turbocharged form a lot more flexibility and tuning parts available for it than the ST170 engine. If you were to stay N/A then I'd say go ST170 but with the turbo in mind then 2.0 blacktop. Dash clocks you could use out of an Escort I suspect or a Focus. Also consider a 2.0 will be invariably cheaper than the ST170 engine