Hybrid 5 mattress for my weight

Hi. We have recently decided, my wife ad I, to replace our mattress which is silent night pocket spring with thin layer of latex on top. It is firm mattress as I've been advised that this level of firmness is adequate for my weight which is 108 kg combined with height of 198cm. We have slept on it for the past 3 years and I have to say it is extremely uncomfortable for me. I'm waking up with back pain and numbness in my arms, so I reckon our mattress is too firm?
We have recently been shopping around for a new mattress and I've found that Tempur Sensation deluxe 27 feels about right for me. I've also gone through your mattress offer, it seems that either Hybrid 5 or Fusion 4 is the right for me. Could you please advise me to make a good choice as I don't want to overpay (in my opinion) for Tempur. I've also read many positive reviews about your mattresses, so I'm keen to give it a go if there is a right one for me.
Kind Regards