Electric fan in lieu of Flex Fan

I took my cuda to a radiator shop that has been there for years asking some questions. I want my radiator to have more capacity just in case I get into stop and go traffic in 90 something degree weather. He told me to run a 160 thermostat and I should be fine. The car hasn't over heated or having problems... but my radiator is just a 2 core. He said try the thermo first then we'll go from there. He said don't by the $600 aluminum radiators that they don't absorb heat like the copper does and they don't last as long. He can use my top tank and use a larger bottom tank (the one I have is to small) and have a large tube (instead of small tube) 3 core between $300 and $350. I won't have to fab up brackets or drill new holes. I don't want to do any hole drilling!

I'm running a puller electric fan with 3600 CFM and the sensor is in the intake. I have a switch to cut it off or on but I just leave it on all of the time.

But anyways does this sound like a fair price?