Will this bolt in without modifying hoses or brackets?

Yes. This radiator uses factory mounting points and connection points — your existing hoses and brackets will attach directly. Just drain the system before swap.

Do I need to flush the cooling system before installing this?

Flushing isn't required for the radiator itself, but it's good practice when replacing any cooling component. Old coolant can reduce efficiency of a fresh radiator.

Can I use this if I've upgraded to a turbo setup after the factory?

This radiator is rated for both the factory 3.5L turbo and 5.0L naturally aspirated engines. If your modifications exceed those specs, consult your tuner about thermal capacity needs.