Complex sentence: Others like Marcie Jones who also performed with Marcie & The Cookies, built their careers in Australia singing with lots of grunt but she sang in the then only marginally popular Motown/Soul style.
Split into simpler sentences: Others like Marcie Jones who also performed with Marcie & The Cookies, built their careers in Australia singing with lots of grunt. But she sang in the then only marginally popular Motown/Soul style.