What are Recovery +2"? Not heard of them.
Ultimately, what do you use your p38 for?
If it is just normal road use, then I suspect almost any standard replacement shock will be perfectly fine. And I also suspect most people would not be able to tell one brand from another. Let's also not forget that in most cases people replace worn out shocks with new items. So, regardless of make, the new ones will always ride better.
If you are building the vehicle for off roading, then a longer shock will give you more suspension travel. Which will translate into a more stable vehicle off road and less lifting of wheels from the ground. But longer shocks will need the rest of the suspension to support the additional travel.