Daily driven NB suspension mods for a bad back

I have a set of Spax RSX coilovers that came with the car, in the trunk.  Does lowering a Miata do anything positive?  What are the best handling mods that dont make it a pain in the lower back? I'm thinking away bars and ditching the 14s for some 15x6/7s with decent rubber would be sufficient along with chassis stiffening like "frog bars" strut tower bracing and those frame rail things.  Car will most likely do the Challenge either stock or with wheels and tires and maybe the coilovers if they dont sell (I'd rather have away bars I think) then it would be occasional track days and autox. Dont know how deep I'll go since I've "raced" everycar I've owned on the street but never on a track

Main issue with lowering them is that it can affect the suspension travel in the rear, of which there isn't that much to begin with. The NB is better than the NA in that respect, but not exactly long travel either.

14" with street rubber (ie, not super stiff sidewalls) are probably a better choice that 15" from a comfort perspective.

For suspension, I'd think good shocks with relatively soft springs, stiffer sway bars and improved bump stops.

As a back pain sufferer myself, I'm assuming you're trying to minimize short, sharp jolts coming through the chassis? In that case, stiffening the tub might actually work against you.

Oh, and strut tower bars on Miatas do less for them than in a McPherson strut car.

Everything I've read about the Spax coilovers was not kind. Widely regarded as junk. There was a set on craigslist near me that were listed for literally years, with no takers.

Cowl shake type movement is the type of stuff I want to minimize, and yes Tim, you know what I'm going for.  Lowering is a standard mod for all the other platforms I'm familiar with, I just wanted to make sure I'm right in thinking this is one car that doesn't need it.  I've read the same about the early Spax, but that the later models were better.  I'd hate to find out my first set of coilovers ever were worthless.  Sways and bumpstops it is, and the 15s may be a very near future upgrade for tire choices and reduced sidewall height

Yeah, tire selection is definitely better in 15".

Cowl shake is definitely going to be improved by frame rails/butterfly braces. I'm planning to do that on my NA once I have the rollbar in.

My NA is lowered slightly now that I have the Konis w/ FM springs in them. Haven't driven it much since but so far I like that combo, mainly because the spring rates haven't been set to stop the suspension from moving.

My NA on Fat Cat coil overs rode fantastic way better than even stock. And that was still at a lower ride height

Can't beat custom valved shocks.  Call Skaikh at Fat Cat and tell them what you are after.  15" tire with a decent sidewall,  55 or 60 series.  Also, the seats in your car are not great, unless they are way better than the ones in mine. Alternatively, you can pick up used, good condition suspension stuff for a Miata all day long. 

Be sure to get new rear shock mounts from Flyin Miata or ISC Racing when you lower the car. Those mounts gain back some of the suspension travel lost. 

For those that misunderstood, I dont want to lower it, just want to verify there's no huge advantage to it before i get rid ofthe coilovers.  It's hard enough to climb out of as is! If I can make it handle any better with away bars and wheels and tires then I'm happy.  Well, maybe a little more power and brakes

Bigger front bar will make it corner flatter.  There is a performance advantage to lowering, but you go too far you sacrifice suspension travel.  Sounds like you are maybe on the stock springs and dampers.  Fresh Koni shocks will make a big difference.  Maybe check out a Miata specific site, like miata.net.

Thanks all!

Getting a little off topic but I have had back problems for years. About three years ago I got a new doctor (old one died) and we were discussing my health history and for my back issues he strongly urged me to get a new car. AND I should be looking at higher end cars like Merc,  Audi, BMW. Lexus, etc. His reasoning was that in the higher end cars they will spend more on both the engineering of and the construction of a seat than many car manufacturers spend on the right tir car. I laughed and asked for a prescription for a new S Class. But he insisted. I eventually followed his advise and picked up a new to me Merc and it has been a life changing experience with respect to back pain. It has gone away. If I use my old truck for a weekend the back pain returns.  At my most recent physical I had to eat a little crow and admit to my doc that he was right. 
 

My Merc is far from a soft cushy ride but it is not a Miata turned gocart either. Since owning it I have not had any more back pain. The seats are not soft cushy things like my truck. They are firm and supportive. 

Anyway back to the OP. If you have back issues I would be looking at the seat in the car as well as the suspension. I had never thought of it until my doc told me to go get a new car to help my back issues. 

I've had back problems since the 90s and I've had Volvo, Mercedes, BMW, etc in that time in addition to 2 back surgeries.  I've had probably 25 different cars in that time.  I wish your suggestion would help but BTDT

On a light car, pay a lot of attention to wheel/tire weight. 

I went to the heavy Chinesium 15" wheels that came on the car from factory aluminum Miata 14" recently (didn't want to wear out new 14" tires until I get a good alignment). The difference was profound. 

Also, for a bad back, get an inversion table. 

FWIW, I'm in the bad back club (degenerative disk disease) and my NB2 is completely comfortable for me. It's on FM adjustable V-Maxx coilovers, FM sways and endlinks, and some 6ULs wearing S.Drives. A little crashy on really harsh hits, but otherwise it's fine... The Fox coilovers would've been even better, but were out of my budget at the time.

I had vmaxx classics and was fine in my NB with reasonably light 15x8s and FM sways

A hard top + roll bar will significantly reduce cowl shake and won't affect the suspension much, if at all.

Suspension is one of those areas where you really can have it all, provided you're willing to pay up for it. My '95 runs race Xidas...it's a tough pill to swallow at $2800, but it absorbs huge road imperfections with barely a hiccup and is absolutely track capable

Konis on stock springs is nice and smooth in every car I've experienced that specific combo in.

Can you fit Recaro Ergonomic line in a miata?  Not cheap, but what is your back pain worth?

https://www.stableenergies.com/Recaro-Ergonomic-Seats/products/396/

There are probably cheaper options for an ergonomic seat, these are top of the line.