I plan to keep the stock 19's. I will be boosting, but 275 is perfectly fine if you're running street DRs.
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I'll likely be running M/T drag radials or Nitto 555Rs. I did really well on the 555Rs.
As long as you have a good sticky tire, you can have plenty of power with a slightly thinner tire. As soon as I get my car above 500whp, that's when I'll be putting a wider wheel on.