They are a good starting point for a stock ratio suspension. Their gas matics will work decent up to XHD leaf springs (around 130-140# rate) and 1.0 torsion bars. Anything above that require more shock control.
Yes, Monroe has several levels of shocks that go up in price. Their basic shock is entry level, Gas matic is next step up, then Sensa-trac, and they have recently come out with a new inertia sensitive unit.