For a pure PvE build, most ppl would go for 3 rchgrdx. It is difficult to give advice without seeing the whole build. I have it slotted with 5 Luck of the Gambler IO's, all of them except the "Defense" one.
5 enhancements from the Red Fortune Set (again, all them except the "Defense" one) are also a good option since its bonuses include +5% rchg rate and some +dmg (I think 2.5% dmgbuff). If you go for the whole 6 enhcs from red Fortune set, you'll also get some ranged defense on the 6th one iirc.
For PvP, on regular IO's, you probably want 3xrchgrdx and 3xdefbuff
Also going for Luck of the Gambler, just missing the expensive one.
UNION @Flitz 50, Lead Hose 50, Red Rag 50
DEFIANT Rose Bloodthorn 34
VIGILANCE Captain Caledonia 20 - Yeah, I made toons on the French server coz we only had 4 back then (might have to transfer/recreate them on one of the US servers)
..and many more!
For PvP I think the optimal slotting would be:
3x Membrane HOs
2x Runspeed IOs
1x LotG +rech
- @DSorrow - alts on Union and Freedom mostly -
Currently playing as Castigation on Freedom
My Katana/Inv Guide
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. -Einstein
i went with 3x HOs
1x run speed.
didnt need a lotg because all the other sr powers took those 
2 run speed is nice, its like unsuppressed superspeed
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
hey peeps im stuck with how i should slot elude on a ma/sr and help/ advise IO's prefered but if not So's r ok thanx