Ok, I have been thinking of getting a Rena XP4 because one of the newer LFS has it priced at $149 or $159. I have not confirmed this with them but their other XPs are priced in a similar reasonable fashion. The XP4 will be going on a bare bottom 180gal tank with either an Emp400 or AC110, along with a Seio pump to circulate the lower water column. Correct me if I am wrong but I have read the XP4 are too similar in design to the XP3s and that is where their downfall is, the motor burning out or not being able to handle the extra 100gph. So if I can get the XP4 for about $40-$50 more than an XP3 is it worth it or stick to the old reliable XP4?