I think 具体的(ぐたいてき)には is a translation for "to be specific".
Also, the following phrase is often used:
(もっと)具体的に言(う)と=If I say (more) specifically,
(もっと)詳(くわ)しく言(い)うと=If I say in (more) detail,
Furthermore, there is another phrase to fit your example.
さらにいうと=furthermore