There are no clear lenses available for the 89-93. I wish there was a set available.
HIR's are just another silverstar version. I have PIAA extreme white plus which are probably the brightest halogens available and they can't even come close to the light output of even a 35W hid. I have seen them side by side and they are easily two + times brighter.
On a two lamp system, you are supposed to change the low beams as they are most used if you can't do both.
Mayhaps I wasn't quite "clear" *grins* I mean "clear" as in "not white or foggy", not "clear" as in "with no refraction grill on the inside".
And, no, HIRs aren't. Although based on halogen technology, they're still not quite a standard halogen.
The MAIN advantage is, since they have a filament in the same location as a 9005/9006, the focal point is not altered so the light goes down the road, instead of just blatting across and blinding everyone on the road. Projectors cure that on HIDs, but a) they're more work, and b) you DO need "clear" as in non-refractive lenses (also as in not foggy) for HIDs to do much good. More work for better output.
HIRs take no redoing of the reflectors (which don't work worth crap with HIDs due to the arc being longitudinal instead of traverse) in the Gen1's. Therefore, they're a good first-step. Plus, they last as long as standard halogens - a big plus on some cars! (It's not that hard to change bulbs on the MN12s, so that's not a big point on our cars.)
The wonderful thing is - there's ways to get more light for ALL of us! I was just pointing out an alternative.
Doing a full projector retrofit, polishing the inside of the lens to get the refraction points out, and careful aiming of bi-xenon bulbs is the better way to do it, yes. Consider the price of all of that compared to a HIR, and the HIR is a more practical approach for some people.
Plus, and here's a BIG plus - it avoids the idiocy of blinding people in city driving and while passing on country roads that is a bad byproduct of "Let's just slap these non-focused HID bulbs in here and call it good!" so-called "upgrades". Always a consideration.
Then again, I'm HIR low / HID high, without projectors yet on the highs, on Grand Marquis clear headlamps on the Cougar. YMMV of course. Interesting point is, with the extra light on the road on high beam, I don't see any FURTHER down the road - which is a bit more important than just the QUANTITY of light on the road, don't you think?
RwP