1) I guess it depends on what the playfield looks like. Personally, I'd only get a new playfield if the current one had lots of artwork damage that couldn't be touched up. As far as I know, TZ playfields com factory clear-coated, so I never felt the need to clear-coat mine. I just settled for replacing a small mylar that was coming up and the rest of the mylars looked fine. Then again, my playfield is very clean with no artwork damage.

I did have some issues with stripped wood screw holes, but I discovered a pretty simple solution. I went out for chinese food and brought the wooden chopsticks home. Then I snipped off a short length of one of the sticks and then snipped the short bit lengthwise to fit the hole. After gently tapping it into the whole with a small hammer, I had no issues with re-screwing and it held in there tight.

2) It might be less labor intensive to cover the side edges with some kind of protective material. Kinda like T-Molding. Maybe you can find some kind of adhesive rubber weather stripping.

3) Some people regard it as a must-have. Others do not particularly like it. Personally, I'm of the "take it or leave it" category. I'm not going to bother putting it in my TZ because I'm not very confident about drilling a hole in my playfield. I run the 9.2 ROM anyway (love the feel of pumping in quarters), so I'd get nothing out of the third magnet. I don't think new playfields come with a hole for the third magnet, otherwise people without the kit would have a big hole in the spiral loop.

4) You can go anywhere from minimalistic to absolute overkill. I veer towards minimal mods, and here's some things that immediately come to mind:

--> I've put shiny opaque colored marbles in my gumball machine. I've also installed the pinbits gumball light kit. These two mods add what I feel is some much-needed illumination and pizazz to the normally dim upper-right portion of the playfield.

--> A reinforced (L-shape support bracket) yellow oblong slot target is an absolute necessity. Because it's so close to the flippers and directly facing them, it takes a lot of punishment and eventually bends backwards and breaks. The backwards bending also exposes the left side of the slot kickout to damage from the ball smashing into it. Optionally, you can also replace your green "clock millions" target with a reinforced version if you feel your default one is taking too much punishment.

--> Get clear plastic protectors to keep air-balls from breaking the artwork plastics. The rocket kicker plastic is particularly vulnerable to this. I think these are a necessity because these art plastics aren't cheap to replace.

--> Build and install a remote battery holder. You can find instructions on pinwiki. There's absolutely no reason to not do this. That is, unless you want to forget changing the batteries one year and have battery acid leak onto your main board.

--> Buy a cliffy protector for the slot kickout. The rim of the wood can get pretty worn over time, and this little piece of metal covers up any wear while preventing further damage. Add cliffy protectors to other areas as you see fit, but this one in particular is a must-have for me.

--> Re-adjust the "Load Gumball When Lit" sign by swinging it counter-clockwise a tad. This makes the Load Gumball lane much easier to see.

--> I don't have one (still debating with myself on it), but a lot of owners like to have a piano mod of some sort. It adds more visual indication of the hard-to-see piano shot.

I'd like to second this sentiment. I highly doubt TZ will get a repro anytime soon. My reasoning? Licensing!

TZ requires not one, but three separate licenses: The Twilight Zone intellectual property from CBS, Rod Serling's likeness from his surviving family, and Golden Earring's song Twilight Zone from Universal Music Group. Producing another run of TZ machines would require re-licensing from these three. It's a huge legal and financial hassle for any small business.

Not to mention that the only reason TZ was ever made in the first place was because Pat Lawlor had a free pass to do whatever the hell he wanted after Addams Family. He said it himself in an interview (it's on ipdb's TZ page) that someone should have reigned him in on the project. The costs of parts and licensing ran pretty high, but it sold okay in the end.