Hey Jim, I think you should go with the Comp cam. I'm sure the 708 cam will work well, but while you are going to all this trouble and expense, you should try to get the most from your setup. Flashing the PCM will not do the same as an adjustable timing set. Changing PCM maps will only change your fuel and ignition timing curves. While these curves can be optimized for a particular setup, it still has a different effect than cam timing. An adjustable timing set lets you adjust the way the cam is installed which directly impacts your valve timing in relation to the crank position. If you advance your cam on the install, you move the powerband lower in the rpm range and if you retard it the powerband moves higher. This is a result of the valve timing events changing cylinder pressures during operation as well of a muriad of other things. There's a lot to cams as they are the brains of the engine, so read up on it and learn as much as you can.
I don't know what kind of spring pressures you are going to be running, but I'm sure BTR is taking into account that you are running hydraulic lifters and probably won't put too much spring for your lifters to handle. As far as aftermarket lifters, there aren't many options. Crower sells an "upgrade" but it turns out they are actually made by Sealed Power. I think Sealed Power may be OEM lifters anyway. Most OEM style lifters are made by the same companies like Sealed Power and Clevite. I'd say most people who have done engine mods are probably still running OEM style lifters. You could always go with Jesel solid rollers. They are a bargain at $2,500 a set.
