Rarely ever is a used car sold without a reason. The best you can do is look it over, drive it around and get a mechanic that you trust to have a look at it. The reason it is on the market will often be evident, sometimes the seller will level with you and save you the bother of finding out yourself. Most times (I have only bought 1 new car in my 40+ years of driving and it took 3 years to sort the bugs out of it!!) it is something you won't know about or suspect until it rears it's ugly head down the road later. I have learned that is just part and parcel of car ownership.
Some makes and models are known to be bad buys but other than that I just buy one that suits me, looks fairly clean and sort it out as I find things.
Oops! This was supposed to go on your other thread! Sorry!
To answer your question on this thread, I do like the smaller bumper look but now you need to do the same to the front to balance out the appearance. And yes it would be difficult to maintain the crash integrity of the stock bumper in the downsized version but it would look so much cleaner!