Neither of those things are essential.

Gumballs
Gumball Light
Paino mod maybe
Powerfield Switch kit is really nice but not needed.

Everything ...... I Miss mine . Skull , Plane , TV , Lamp Post , Clock Led's , Sooo many More

How about using the search function as this thread has been repeated many times previously.

The inexpensive spiral mod has big impact - http://www.pinballdecals.com/TZ_SpiralDiverterModPage.html

and #1 - spend $300 and get invisiglass ...

Anyone do the third magnet mod know if its worth it?

I was in your exact same boat last month. Got a completely unmodded TZ. Here is what I bought:

1. Piano, Camera and Diverter magnet from pinballpro ($130) -- these were the most essential to me.
2. Gumballs from pinballlife.com ($10) -- well, and these too.
3. Color changing door kit and chrome side mirrors from cointaker ($170) -- aesthetics
4. Greed, clock and slot decals from pinball decals inc ($40)-- I like these a lot
5. New powerball and custom powerball shooter rod from pinballlife.com ($47) (out of necessity. The old ones were bad)

Only thing I want to do now is the gumball light mod, and maybe the door flashers. There is a really cool rocket mod on eBay but its $155 and I'm completely spent!

I bought Robby the Robot, the camera and the rocket ship for mine. Te robot is awesome but was $180 on sale. I need the piano.

I'd say do one at a time. The first and easiest one is the gumballs in the gumball machine. I used the plastic marbles from a chinese checkers game. These are the ones I bought and used:

http://www.quill.com/classic-games/cbs/220083.html

Free shipping, no tax(for me anyway, not sure about for BC). If you get just one, it'll fill up half the gumball machine to match the level of the pinballs in it(if you don't use the black gumballs). If you want to fill it up, then get two. Plus, these are a little bit smaller in diameter than the ones sold by most pinball supply places, allowing you to put more in, giving it more color. I also like these better because they ARE plastic and not glass. Real gumballs aren't super shiny and if the idea is to mimic real life, matte finish-like plastic is the way to go. Just make sure to count each of the colors out evenly otherwise you'll have uneven dispersal of colors in the gumball machine and it looks a bit odd.

After doing just the gumballs, I've decided against some of the other mods. The only other mods I'm considering right now are the piano and original TV version camera mod from pinballsmith(pinside name). He's currently working on the piano one and it should look fantastic, but I'm not sure about the camera one. I know he made the one that looks like the one on the playfield(and sold out of them on eBay already, too), but I'm waiting for the TV version.

I'm patient....

(mine already had the diverter magnet done, but it is a MUST do, too)