I think those, that say they don't, don't believe the kickback damages the turbo. Lot's of those that believe they are not necessary only drive their cars on the track so the turbo is subject to wot or idle...nothing in the cruise mode.
[This message has been edited by Steve Wood (edited December 03, 2001).]
Some recommend them as Steve said and they do save the Turbo thrust bearing especially with a large Turbo! What size turbo are you running? Check with Pat Rubio on this site as he runs one on his car RU. I'm using the ATR one but there are several available, your choice. Gene
With a MAF car it's best to run a closed loop "sneeze valve". Unlike ATRs, which is good, this style dicharges the metered air back into the turbo and engine which reduces surge on the turbo. It also, as mentioned by others, eliminates the off throttle bog and stall. Explaination available upon request. We offer an inexpensive kit for about $100 that works great.