that because ripcurl makes terrible wetsuits. 5/4/3 is all your need. I find ripcurl to be the worst wetsuits on the market; by means or their neoprene and seams. Get yourself an xcel 5/4/3 and your be plenty worm....if your looking for a little sum thin sum thin a little cheaper go hyperflex amp 5/4/3...or if you really want but totally unnecessary a 6/5/4 by them.
I have a 5/4/3 Flow by HyperFlex and I have to say its the warmest suit I have ever owned. I have stayed out for up to 4 hours with not a chill. I am to the point where I am sweating in the suit. I have there new 5.5mill gloves . I am not a glove person but there gloves are so warm and comfy they changed my take on them . As for there boots I wanted to get there 7mils but they were out of my size so I had to get rip curl but I am happy with them as well.
If you can take the extra rubber of the 6/5/4 go for it. I think you will be very happy and surprised by there 5/4/3
I have the west lotus 6/5/4... its warm. I only wear it when the water is less than 45, and the air is below freezing. Its hard to get out of, sort of a weird closure system.
Its pretty stretchy as far as 6mm of rubber goes, nothing compared to how stretchy my 5/4 oneill is though. Your main concerns, however, seem to be warmth and price, and this suit has both of those going for it.
I have a 2010 Hyperflex AMP 6/5/4 size LT never used with tags still on i will sell for $250. Great deal you cant get them for under $270 online plus shipping. Hit me up with a PM if anyone is interested i am going to post it on ebay in the next few days.