You'd better let Power2Max know...
No need, they know.
Really, this is just simple physics and engineering. A crank-based PowerMeter has a number of potential error factors build-in to it. Among these are the chassis, the crankarms and the rings. If you change any of these factors, the slope can change. The issue then becomes one of materiality. The manufacturer will typically forward the PowerMeter with the chainrings. If not, they can substitute a common chainring (e.g., with a DA 7900 SRM, the stock Shimano rings) torque them to a known spec, calculate the slope and ship it with that information. If that is within the advertised error factor, then they are good-to-go.
If you change the rings, does it affect the slope? Of course it does. The question is: is that material? If you use rings of the same size from the same manufacturer, the variability is much smaller than if you change to rings of a different size from a different manufacturer and still greater if you change from a conventional ring to, say, a solid TT ring.
As long as you can re-calibrate the slope yourself, which you can do easily with an SRM, you will have no problems.
The other thing to consider is whether or not you need to even worry about it. The only reason that the accuracy of a PowerMeter matters is to ensure that the data generated is consistent. Aside from comparability year-over-year, it really doesn't matter whether it is measuring high or low. As long as you are testing to the same numbers and completing your workouts at prescribed wattage, that is what counts.