Tubluar Suspension kit on ebay, Any good?

I think this is really affordably priced, what am I missing?

http://cgi.ebay.com/ebaymotors/ws/e...&item=7926799945&rd=1&sspagename=STRK:MEWA:IT

The D&D kit looks nicer, but a little more:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7926710716&category=42609

If I were to get one of those, would I need to get caster plates like these:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7926444490&category=33581

I plan on road racing this car when I'm done. I've decided to upgrade suspension, rigidity, brakes, and rims first to get the car turning and stopping greatly improved over stock. This stuff looks like it will greatly improve and lighten the front end.

I like to D&D stuff over the Ground Pounder stuff. It to me looks better and they list how they make it. Has anyone had either of these kits or one like it? Is it going to dramatically improve handling? The weight loss make for any noticeable acceleration / braking improvements?

Autocrossing, Drag, slolam track.

I was gonna ask GP, D&D, and Maximum what gauge steel they are using for this stuff to see if its any thicker. If you look GP actually links you to other places to check other stuff out and see that its the same looking, but theres is the cheapest priced.

Looked ath Maximum and D&D's websites. They seem to have the same methods and quality of material on paper. I really am liking quite a few D&D parts on paper, hoping to pick some stuff up after I sell my other car.