This guide assumes that you have read the previous guides, have arrived at level 115, achieved max kill of 15 monsters, started pushing through Pit of Greed questline and have several pieces of T7 gear and working on the rest. This guide will cover the progress through level 115 (T7) to level 130 (T8) and will mostly be about hitting certain Attack Speed stats. Other than speed, the importance of allstat will be extreme at this point, along with hitting several of the speed compendiums.
Also, the slowest completion of quests will take place. Don't panic, stay calm, grind compendium.
Acquire T7 sidearm
As the Pit of Greed questline doesn't require that many kills, even killing 5 monsters to complete a single mission is an acceptable loss. The goal is to finish the The Final Push I quest, quickly reinforce and empower it and get it to 10*. Until you get more T7 equipment with 10* or above, don't go further in the questline: it becomes a massive slog without too much important rewards.
However, check the market to see if there is an exceptionally high empower (13* or above, maybe 12*) level T7 sidearm on sale: this will save you quite a lot of effort for the later part of this guide). As reinforcing the T7 sidearm is much cheaper than any other T7 equipment (+10 instead of +16), it's not that worth to pick it up since the base stats of the item will always be the same, unless you're in luck and said empowered equipment is on sale.
T8 Sidearm and rifle are using 8.5 cores, so you will be keeping the T7 version the longest.