P5-6 vs P5-3 is 1 watts
P5-3 is essentially the same as p3 or p2 frameset as long as each bike as same major components (bar, brakes mostly). There are small differences in the frameset of the p5 but those differences are at the back of the bike and we are talking 1 or 2 watts.
that how good the p2-3 frameset is. The group, crank, saddle you put on the bike have very little impact on performance.
So, once you treated your P2 to the ''p5 components treatement (fork, fairing, beard, magura, adruo bar) you will be ahead of a shiv, Felt IA, Speed concept for anything from 0 to +/- 7 degres yaw.... and might get caugh up by the speed concept at higher yaw but you essentially are riding a super bike for a very affordable price.
so, 2000$ for a 2017 closout p2, 200 for a p5-6 fork, 400$ for aduro, 150$ magura brake 75$ of fairing, beard etc
2825$...... for perhaps a 3 watts deficit on p5-6.