Cant comment on 172s as havent had one/got mine yet. However, my Dad has an MGZR 130. When he took it in for its 6000mile safety check the mechanic said "Thank god someone is using the rev range on this car. Most of these come in for their first service all clogged up because the engine hasnt been opened up at all, and the old grannies that drive them tootle round town all day at 20-30mph". However, he did add, that the first 500miles should be taken easy, and after that limit, power should be tested in bursts.
As for thrashing cars, if you run it in for 1000miles, and then thrash it silly for the next 12000, you can expect rattles and things going wrong. A friend of the family who works for Ford Rally Group told me that that is why rally cars workings dont last very long... they are taken to the limit continuously. The performance road cars might have flash stats, but they are not designed to exceed more than around 85mph for continuous and regular driving.
When I get my Cup, I shall certainly be running it in for the first 5-6hundred miles... ok I might drive to Edinburgh and back the first weekend, but hey... Im going to do it.