Basic way to think about it, the larger the camshaft duration, the higher it will move your peak torque in the rev range. The larger amount of lift, the more power they will deliver.
That's a very simple way to think about it, but does apply.
Main thing you have to think about is whether or not you want to keep the VCT. Get rid of it and you will drop power down low.
So if you don't care about VCT, get a set of 264degree cams on intake and exhaust, or if you want to keep it, go a set of poncams, HKS (256 or 256/264).
You just dropping the cams in, or doing headwork? I highly suggest you do the valve springs at the same time, I found out that one the hard way...
EDIT: Yes solid lifters will allow you to run larger cams and have a safer peak RPM, 8000+ (aslong as the bottom end is balanced well). However the amount it costs to do the conversion is more than you would think.