First of all congrats on your purchase, that's a great car!!! On the subject of your G50 that depends on how your going to use your car!!! If it's just a road car for tooling around on the streets then not really but if it's going to be used on the track then I'd say yes !!! It's up to you in the end .
If you intend to run the car at a track pace for more than an hour at a time then you are venturing into the profile that would begin to require external cooling. Two hour races and I think the answer is yes. I have a G50 in my SLC with a temp sensor in it. I have not seen temps above 225F after 30 min on track sessions with ambient air temp above 95F and track surface temps above 125F. I run R6 Hoosiers and a 450hp SBC.
I agree with Bob. You don't need a pump and cooler on a street car.