I've been through it with a modified tank that was chopped to accommodate wheel tubs... cracked a seam and leaked , especially when particularly full... removed the tank, cleaned it out thoroughly at the local coin op car wash and got it welded... $200+ dollars later got it back in and it don't leak no more...

If I had the option, I would have definitely gone with a new replacement and even at that if I had to do it over again I would have gotten a fuel cell and mounted in the trunk for about the same cost as repairing the old one.

pin holes on the other hand... I would listen to Brian...

-Chris