I once had wheel-bolts on a Mercedes that the dealership had overtightened. To get them undone, my tame mechanic had to use a 5-foot extension bar - and even then had to work really hard at it! He succeeded in the end, but the bolts had been so abused that two of them sheared off whilst being undone, and several others had visible signs of having been stretched. Even if there is no visible damage to the bolts, you should consider replacing them - you never know whether bolts that have been overtightened like that have been significantly weakened, and the cost of a few bolts is going to be a lot cheaper than losing a wheel at speed!
Colin
