This patch is designed to let players complete No Stone Unturned without joining the Thieves Guild - after all, Vex would have to be pretty stupid to turn down an opportunity like this just because you're not a guildmember.

Conflicts are extremely unlikely; the only records modified in any way are Maul's dialogue and the TGCrown quest, i.e. No Stone Unturned - asking Maul what the gem is worth will set TGCrown to stage 10 instead of stage 5, and removed the IF TG01 == 1 requirement on Vex's dialogue relating to the gems and crown, bypassing the usual need to join the guild and do the debt collection quests. All her other dialogue remains locked, save for the Lockpicking training which appears to be always available.

You may also be interested in Non-Quest Locations for Stones of Barenziah, which relocates the three quest-locked stones (from the Dark Brotherhood, the Archmage's Quarters and Proudspire Manor) to less annoying locations.