I don't think it necessary to throw millions at the squad but it does need some investment.
I remember McLeish (and I wasn't a fan) saying he preffered to meet potential signings face to face to assess whether they had what it takes to play for a club like Rangers. I assume he meant mental toughness and a real desire to win every game. Now I think we can all see what he meant as some of Le Guens signings thus far do not seem to posess those qualities. Guys like Sebo, Sionko and Svensson have been far from convincing since they arrived.