I think this would be really good, Ive never driven a Boxter (nor indeed any Porsche if Im honest) but I gather the Boxter has a fantastic chassis & is top of the class for handling, that opinion seems unanimous. A 180bhp version would still seem very fast to most people (in a lightweight car such as the Boxter) & would just take that amazing driving experience to a wider audience.
I believe the original 911 was sold for a while as a 4cyl, called the 912, if Im not mistaken? So its certainly not betraying Porsches heritage, certainly not as much as the Cayenne & Panamera are =D