I have a Spacer, its the Gen2 of the ZZP and i've had it for 4 years with no issues. Then again, before I was ICed I had the coolant ports on my LIM tapped and plugged so I never had a coolant issue. I got no vacuum leaks anyway!
Only reason I got it, a guy I knew was upgrading to an LS1 TB so he practically gave it to me with something else I got from him. I installed it and before I was ICed I noticed the TB stayed ALOT cooler, at the most getting lukewarm. After installing an IC the TB stays ice cold, as does the S/C, but the TB is a little cooler due to the spacer... and this is on a 95-100 degree day. You can imagine how cold everything is this time of the year.
I'll probably keep the spacer on there. It certainly doesn't hurt anything to have it installed on there now. If anything it prolongs the life of the sensors. I haven't had many problems with the sensors on the TB, this maybe why. Besides my CAI, TB spacer, and IC combo works damn well together and it cools like its suppose to. As they always say the coolest, more dense air is better than regular ol' hot air. I thought about running alky at one time, which I doubt I ever will. But if I ever decide on a Dry Shot, I have a perfect spot to tap in.
So is a TB Spacer worth it? Probably not the asking price, not unless your going alky or nitrous anyway. Although the cooler TB on a non-IC car wouldn't be a bad thing. I'd doubt you'd gain .5 HP though. Does it help my setup? That debatable. I'm sure everything would work just as good w/o the spacer. But the slight cooler TB doesn't hurt either. Oh well, it works so i'll leave it be. Probably a .5 HP on my end too! LOL
Would I buy one today if I didn't already have one? No, I doubt it because I would probably say its useless on an IC setup. Now if I was planning on spraying... yeah i'd buy one for my nozzles and thats it. I doubt i'd buy one new for a non-IC setup honestly...