So what you are trying to say is that for the OP's budget of $250-$350 your rear cradle inserts will perform better than our full rear cradle bushings? I am definitely not going to agree with you on this. Also I am sure the guys you have on that list are using these rear cradle inserts since it is the only rear cradle inserts/bushings you have available that are within the OP's budget?
The way I look at it is that you have someone that is on a tight budget and looking to get the most for their money. Their budget is $250-$350 which they clearly say in a post in this thread yet you are wanting to try to sell them something that is twice the price and compare the parts they are looking at to something way more expensive. That makes perfect sense.
I am definitely not saying that there aren't better performing options out there that are pricier but it isn't within the OP's budget. Solid rear cradle bushing would be the ideal choice since it will control the rear cradle movement better than any poly-urethane bushing will which will lead to better overall performance but I am not going to recommend them because they are more than the OP is looking to spend.