Handling Difference between DSE Speed Kit 3 & Hydroformed Subframe?

[kiwigt]

I intend to install DSE front and rear suspension on my 69 Camaro. Where I live, suspension changes require an engineers certification process to be permitted on the road - and a chassis change (aka DSE hydroformed subframe) is a whole lot more engineering certification pain than suspension modifications (aka DSE speed kit 3).

I'm looking for comment on the real world difference the DSE hydroformed frame advantage of spindles and rack and pinion etc would make in reality , over my apparently easier option of speed kit 3?

Do they drive much the same?

My car is 100% street driven, no auto x etc.