I've got maximum motorsport full length subframes. Pretty happy with them. Not the best money could buy but I did notice a much more rigid chassis with them in. The hans racecraft stuff looks pretty sweet tho.
If you're looking for the type that are triangulated with jacking rails, there's Hans, Global West, and Kenny Brown. They all look pretty nice. I have MM FLSFC's on my droptop but looked into these others for further tightening up of the structure. The Kenny Browns seem most cost effective, but from what I ave read are a PITA to install with the zinc plating on them. It's difficult to get a good weld without the zinc contaminating the welds and weakening them.
I just had MM FLSFC installed on my about a month ago - well worth the $$ to get it done. I know there are other, better ones out there, but it would be overkill for a daily driver like mine.
FWIW - 95% of the creaks and groans are gone after the install.
Finally, the correct answer. They are also the best strength to weight ratio.
Most people end up not wanting to use the best however, once they find out what the best actually is and how they are installed.
It is a shame too, because verts really need, and really benefit from a nice through floor SFC. Specs and instructions are on the web to fab these from readily available steel stock, and they can be done for less money that way.
The labor is still significant though.
Too many people mistakenly think that they are hurting the resale value, and won't use them, yet there isn't sufficient enough resale value involved to justify not using these.
The difference between these and normal SFCs, is almost as great as none vs normal SFCs.
Just a head's up before anyone gets too weepy eyed over the Griggs SFC. If you go ahead and cut up the floor pan and do it right, you'll also have to ditch your motorized driver's seat frame and get a manual seat frame. I seriously looked into that SFC when I had my 98, but in the end decided to go with MM.
I was going to install the Hans but the set I got did not line up correctly so the install was aborted. After feeling the weight of them which must have been at least 70 pounds, I was not too sad about it. My installer also makes custom roll cages, exhaust, etc. and they have the mandrel benders an such. So after talking them, I went ahead and had them make a custom set of chromoly matrix style subframes. They turned out excellent and they only weighed 26 pounds total. Huge difference. Though I ended up paying about $1200 total for everything. Not the cheapest, but I feel it's the best I can get without through the floor subframes.
I've got the full Kenny Brown Extreme Matrix and I love them. I tried getting the HANS kit, but I couldn't find them at the time. Considering KBP was down and out at the time as well, I was surprised to find theirs first. Any SFC will hake a huge difference for a convertible.