Porcelain Veneers are a wonderful cosmetic dentistry option that is useful in many situations.
The real question that would help better answer this question is why you are considering doing porcelain veneers on these teeth:
1) If you are happy with all your other teeth and simply have chipped or discolored front two teeth, then porcelain veneers may be an excellent option. If this is the case, consider whitening the other teeth prior to doing the veneers. It is a definite challenge to do two veneers and create a natural and blending affect with the adjacent teeth, but it can certainly be done with custom porcelain layering.
2) Another possibility is that the two teeth are crooked or rotated. If this is the case veneers may also be nice option and the same information from #1 applies. In this situation you might also consider minor orthodontic care.
Doing two veneers can definitely be a smile changer in the right circumstances. I hope this helps.
Ronald W. Konig DDS, FAGD , LVIF