I have no experience with Hot Racing shocks but I have used a lot of their other parts. They make very well machined 'pretty' parts but I've found them not to be all that durable. Just my experience.
As I mentioned before, JennysRC has brand new factory takeoffs and after a quick google search, I found the rear shocks on an Arrma Bigrock 6s to be 134mm which is pretty close to what your looking for. Those shocks are common enough, you should have no trouble finding an assortment of springs to match up to the weight of your vehicle if the supplied springs aren't already close. For $30 usd, seems worth a shot.