Hartman vs Tracks USA

Looking into longtracking (144) my sxr. Can anybody school me on the difference between the Tracks USA and Hartman extension kits? Tracks USA is quit a bit cheaper. I would like to run a 1.5" lug with stock 9tooth drivers, no studs, tunnel protectors removed. Maybe drop 1 tooth gear, go from 22 to 21. I am more than open to opinions and suggestions, as i have never done this before. I appreciate any info. Thanks

must be top secret?

We've done almost exactly what you said. I have only done Hartman rail extensions. My 96 XT6s 144 tip-ups and my sons 99 SX6 136. Both fit very very snugly. We are talking @ .010 tolerance. Perfect fit & finish. Not anything here to b!tch about. Quite the opposite.

Hartman tunnel ext (fit and Finnish way better). Track USA rail ext (fit and Finnish better) also much more durable. Put 144” on my vipers years ago and still perfect.

Thanks guys.