The way some of the wording is written. I know a few guys who have worn the groove legless briefs in Raw. I think APA and 365Strong allow it????? I have no idea of the Legless groove briefs even add anything. I'm not sure if it's legal or not. They may have been cheating. I know a few Feds allow briefs under single ply suits and still count as single ply.
edit: re-read the APA rules and it's illegal in Raw for sure.
http://www.inzernet.com/detail.asp?PRODUCT_ID=GROOVE
I bought a pair of the inzer Power Pants once and never good get the sizing correct. I have a Titan cent. briefs and love them.
My first suit was a Metal V-Style squat suit. I used mainly for Deadlifts. When my hips hurt I would wear it with the straps down. Took all the pain way instant. I have bought two of these suits used off of PLW for 30 bucks each.
I would try and find a suit like that to train in. Then you can try out single ply squat and deads for fun. Push the limits a bit more.