Just letting you kno the sewer trial is 38-42 
Nofuture Guide
thePhilosopher Martial Arts/Regen/Fire Scrapper
theRegulator Empathy/Energy/Soul Defender
Total Inertia Ice Blast/Kinetics/Psy Corruptor
Total Inferno Ice Blast/Thermal/Leviathan Corruptor
bugger :\ i wonder which guide is wrong then 
most likly gameamp.com's guide
I've done it it is lvl 38+ surprised gameamp got it wrong tho
thePhilosopher Martial Arts/Regen/Fire Scrapper
theRegulator Empathy/Energy/Soul Defender
Total Inertia Ice Blast/Kinetics/Psy Corruptor
Total Inferno Ice Blast/Thermal/Leviathan Corruptor
the lvl ranges are complicated, but from what I recall it's:
to join: 36-50 (no auto-exemps)
to get the trial from contact: 38-40 or 38-42 dunno exactly
to get the weapons: 36-42
enemies: lvl 42 rikti (on heroic)
"god, how many devs did hami have to sleep with to get ED?"
Total Cat @Stagefright
I did the trial about a month ago. You can pick up the weapons even when exemped from 50. The guns are massive and you keep hold of them after the trial for a few hours!
original post changed due to fact im low level than min requirments for the sewer trial