ant-sri-200

hi all im ant from oldbury west mids , i drive a astra mk 5 cdti sri 150 , im thinking bout doing a mk 2 cav project with a z20let engine and box so thuought id get on here , and see what u ppl think , im just in the process of trying to find a cheap mk 2 to do the conversion on , but dont no which model would be best for this