The term "too jarring" makes your question hard to answer. Add to that the fact that I've never driven a TCP suspension kit (R&P only) and I wont even try. But I will say this...
The TCP design is for track or serious street, that makes me think that the ride will be on the harsh side to begin with. But if you are already running high-pressure gas shocks and stiff springs I don't think you'd see a huge increase in overall stiffness.
If you are afraid to run poly up there then you are justified to be wondering about these units. According to TCP they have linear deflection unlike rubber or even poly, but there's no mention of just what sort of resistance they have to deflection.
Even if you run nearly solid on the strut-rods all it will do is limit fore/aft movement of the LCA, plus add something to the springrate.