I guess that all depends on your idea of "top end" and what results you are after! The OP's phono stage is certainly not up to the job and whilst JR149's can be very good much depends on condition. They do tend to "go off" over the years. The last time I heard a set was about 12 years ago and they were old then. This set looked in tip top condition and all the drivers worked. A mate in Leeds bought them. We tried them with a Stereo 20 and they sounded awful. I knew how good they could sound from being at hi fi shows when Jim Rodgers was demonstrating them! Thinking they maybe didn't like the Stereo 20 we tried them with an Exposure 4 DR with the same results... Knackered drive units? Worn electrolytics in crossover? Gawd knows...He sold them on a few weeks later.
Stereo 20 is good (better still modified of course
) but there is much better around like an Art Audio Quintet for valves or a Sugden A21SE for transistors.
With the OP interested in a 3009 arm with an MC cart as well it's looking pipe and slippers-ville from here! If never sounding harsh or in yer face, even if the recording is meant to, is the over riding requirement then it should be fine....