I know in the mobile they make the mirage MX-36HP3 with the irf-520's, then the Superstar ss-36hp3 with the rt1's. Same main pcb, actually identical with the difference only being the mosfets used. The mirage claiming 50 watts and the superstar claiming 60 watts.... I'm willing to bet there's only some bias and capacitance changes. For a supposed +10 pep I don't know that it's worth the difference especially if once it's cleaned up you end up with the same 50 pep. For a short while I owned the ranger 39vhp with those rt1's and I'll say that thing would really talk but the final section was 1 520 driving 3 rt1's for about 80 watts pep. Not that it really matters much but curiosity kills me so I can't help but wonder what those transistors really are because we all know ranger doesn't design or produce semiconductors so they have to be a relabeled part.