My suggestion is to continue under the car. You will have to add metal gussets to several joints. If you have not planned on it. A front strut bar will be needed and a brace from the lower doorpost to strut top support is recommended along with subframe connectors. Do you have at least a 6 point roll cage in the future? If you do you can plan all your points to make your chassis very rigid.
Thanks for your input! Seam welding under the car will probably happen after the roll cage is in. We are building the car for ARA stage rally. The cage will be built to the required FiA spec. Plus, we are tying in the front strut towers (3 points each is the plan) and at least some rear suspension mounting points into the cage. We will also be adding sill bars for extra leg protection in case we slide sideways into a stump or something. That should help make the car plenty rigid I think. I've gone back and forth in my head about adding extra support with gussets and possibly subframe connectors. Like you mentioned, the cage will affect how much and where that is needed. Since I don't think the cage will be in the way of most of that I'll probably just wait until it is in and then decide what areas need a little more help.
My suggestion is to continue under the car. You will have to add metal gussets to several joints. If you have not planned on it. A front strut bar will be needed and a brace from the lower doorpost to strut top support is recommended along with subframe connectors. Do you have at least a 6 point roll cage in the future? If you do you can plan all your points to make your chassis very rigid.
Thanks for your input! Seam welding under the car will probably happen after the roll cage is in. We are building the car for ARA stage rally. The cage will be built to the required FiA spec. Plus, we are tying in the front strut towers (3 points each is the plan) and at least some rear suspension mounting points into the cage. We will also be adding sill bars for extra leg protection in case we slide sideways into a stump or something. That should help make the car plenty rigid I think. I've gone back and forth in my head about adding extra support with gussets and possibly subframe connectors. Like you mentioned, the cage will affect how much and where that is needed. Since I don't think the cage will be in the way of most of that I'll probably just wait until it is in and then decide what areas need a little more help.