Lower mkvi jetta tdi for fuel economy.
 

I recently bought a brand new jetta. I averaged 40mpg of the first few tanks driving like a maniac. Now I'm hype emailing getting between 54 and 58.2 mpg on 40mile trips. I'd love to get to my goal of 60 and do think the car sits a little high, but is it worth lowering? Should mileage improve? Is it worth a rougher ride possible undercarriage damage and the pain of getting in and out. I love the car but I must say it is NOT. Fun getting in or out.

Have you done any other mods? I'm sure there are several viable options before the rather expensive option of lowering.

No other mods I'm not sure about the practicality of a grill block especially living in Louisiana. And I dot find 200$ rather expensive. I'm not in it to save every penny otherwise I'd have a 2,000$ car but more or less bragging rights and less money in petroleum companies which ironically I work for.

I'd be suspect of a $200 lowering kit but that's your choice to make.

As far as I know Diesels can be quite aggressively grill blocked provided an intercooler and intake still receive suitable cool air.

Otherwise things like tyre pressures, smooth wheel covers, tyre spats (if done properly) or even rear wheel covers can give simple and effective improvements.

VW regularly lowers its "eco" models. Or "blue" models or whatever it calls them.

It will probably help, BUT the effect will likely be small enough that it is lost in the noise of tank-to-tank variability. EG: probably too small to detect.

In other words, don't bother doing it if you're expecting big gains and can't live with the side-effects you listed.

It's not a kit just h&r racing springs.

Now you say about the intake air. But what's up with all these people doing warm air intake. At the price of power couldn't I just block the whole thing.

I'm very scared of doing any kind of grill block. I couldn't imagine how the vehicle would stay cool or a/c would work (if it was on)

Tire pressure is on point. Stock has tire spats. I refuse to do wheel covers or pizza pan wheels.

If you don't think lowering would make a 1-2mpg difference then I won't put it on my ASAP list.

Lowering a vehicle will improve the fineness ratio and slightly reduce frontal area. Now, to what extent ? It will vary from one vehicle to another.

Welcome and congrads on your new ride.
You might try searching the numorus threads on lowing.
There quite a few.
You want a 50% increase in mpg but don't seem willing to explore ALL options.
I strongly doubt that the grill block will be detrimental.
Maybe you should read the numurous thread on grill blocks

What you may not realize is that lowing your car is much more detrimental to the life of your car than a grill block.
Never seen a lowered car that doesnt have a beat up suspension system after awhile.
And since high psi has a greater impact on mpg than lowering, you will want to soften the tires with a lower suspension. Certainly a lose lose.
On the other had, I hae an IMPUL body kit on my Q45 and that is like lowing the car 2" and still hae a quality ride.
Even a front air dam is more practical.

If hype emailing replaces driving trips, I can see how that would save gas! :P

Which would have detrimental affects on your dampers/struts/shock-absorbers, whatever you choose to call them.
Diesel's operate differently to petrol engines.

Then I can only suggest one of several ODBII compatible systems that will allow you to monitor coolant temperature.

As do I.