Matching load ratings on michelin pilot super sport front to rear

[Schroeder]

I'm putting MPSS on my 77 ta. 285/35-19 on the front and 325/30-19 on the rear. The rears are only available in a 105y load rating. The fronts come in 99y and 103y. The 99y would b yhe exact same diameter as my rear 325s. The 103 I'd .2" in diameter larger than my rear. The 99y is what GM puts on the rear of the vettes. Which one should I get for the front of my car? I talked to a tire guy and he said he'd go with the 99y because I was gonna stiffen the ride too much. Each tire wi the a 103 rating will handle roughly 400lb more of load. Granted, he doesn't have any experience with racing. Car will b 90% street driven. I thought the stiffer tire may help fight undeesteer, but im not sure. I dont what way to go. Load esting is something i basically ignore usually. What do u guys think?

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