Small problem with your argument (well, two...)
1) The Shroud of Turin is not central to (or even any part of) scripture, teaching, or dogma. In fact, most Christians believe it to be a medieval construct as well, and it remains a curiosity at best, even among the majority of Catholics.
2) The alleged tomb that Jesus was laid in is probably not the one - that particular spot was picked by Helena of Constantinople nearly 4 centuries later, based on some local legends. She also allegedly found the cross, but that's most likely bunk sold to her by locals who were eager to curry favor. As with #1, it has approximately bupkis to do with scripture, teaching, or dogma (Heck, the Council of Nicaea probably hadn't even convened yet when this alleged tomb was found.) Today, it serves as a nice place to worship, and to meditate on the Passion and Resurrection, but it has no real significance otherwise.
Meanwhile... the Quran is the actual scripture of Islam; if it was found to have existed *before* the founder existed (let alone wrote it, received it from Heaven, whatever)? That's kind of like kicking the pillars out from under a rather delicate tower... it would be akin to finding a written account of Jesus' life that carbon-dates to 30-40 BCE... now *that* would be faith-shaking.
All that said, here's the fun part: the calendar we use is rather error-prone and isn't fully accurate. Most scientists and archaeologists know this, and correct for it. This is why Jesus' actual life may have begun as early as 6-10 BCE. I'm hoping these guys in TFA have managed to do those calculations for correction, and more important, did them correctly... because they're about to buy themselves a rather nasty shit-storm if they didn't. Even if they're right, I'm willing to bet that the very first counter-argument will point right to our calendar's not-so-perfect history.