Those are two very different engines. The innova 2.5 uses a common rail engine. Turbocharging your 2.7L will make substantial additional power but aftermarket Turbo kits are quite expensive.
BTW, Hyundai Starex' engine is really powerful. It'll be more powerful when they release the
VGT version (Variable Geometry Turbo). It'll probably make 170hp using the same engine. The 2.2L SantaFe CRDi
VGT has 150Hp/335Nm Torque (180Hp/395Nm with upgraded ECU). The Hyundai CRDi 3.0L CRDi VGT produces 240Hp/480Nm (stock performance) which powers the Veracruz LUV.
The only thing i hate about Turbos is the need to cool it down. No one has thought of hypercooling it yet (AFAIK). You need to idle for a minute or two to cool your Turbocharger or it would fail prematurely due to overheat (and it's very expensive to replace).