Will swapping harmonic balancers cause any issues ????

If you're using a fresh stock replacement on the engine now, I'd leave it. If you want a SFI approved unit for a upgrade, and being a street car with just the occasional 6500 blast, I'd look into the "Summit" unit. At less then 1/2 the price vs the ATI, it's a no brainer for me. :)

http://www.summitracing.com/parts/sum-c4277/overview/make/dodge


Engine wise, I doubt you'd ever hurt this one. The only issue that may come into play may be getting the pulley alignment just right?