W5 Pros & Cons

Be very careful.

W5s had some serious issues with porosity and quality control that are well known.
Apparently the one's with the blue core plugs are the better ones. I would be skeptical because anyone could change the color of the core plugs to get their money back. If you do go ahead you will need to find somebody that knows w5 heads and have them tested, pressure checked and gone over with a fine tooth comb.

If w5 is what you want? Head ttowards indy to get their aluminum rectangular port w2s.