Comparing Vi-Spring to your beds please as want to buy quality

I love the feel of regal v spring and note your helpful guidance - - do u recommend I try V tiara to gauge the relativity of your equivalent 002 . As I would like to buy the best within a realistic budget. Just for assurance why does V spring offer lifetime guarantee and yourselves 10 years- is the steel quality the issue - is the price difference all down to marketing etc? How many turns do your springs have in the 004 and 002 please?If I have 002 or 004 would a latex topper spoil the effect? Would I need a mattress cover on top of the topper ?I currently have latex dunlapillow and my hips and back ache