Sasha D

My 83 Cab died the other day, and my shop has indicated that the CDI has gone out. The CDI that went out is a Permatune unit, rather than the Bosch. My mechanic says the Permatunes are terribly unreliable, and the company is such a pain to deal with, that if it were to fail, he wont warrantee it. Cost to replace ...$400. The Bosch unit is reliable and warranted, but the cost to replace it is somewhere in the $1800 range. He also said there is something called a MSD Unit, that will work great but needs some kind of tack adapter that has not yet been marketed, so he could install it, but I wouldn't have a tack until he gets one developed. Cost $500. My general leaning is to just pay the $400, and if I have to replace 3, I am still paying less than the Bosch.

Greg-slant/cab

I also have a permatune unit and found them to be very helpful. I thought I had a bad unit but after testing and speaking with them it turned out to be something else. Here is there technical website
http://www.perma-tune.com/Tech_Support/Porsche/911.htm

The site has a very easy to follow check procedure for it. I also called them and was able to talk to a tech...not a saleman and found them to be very helpful and knowledgable. After we determined that my unit was OK he even offered any other tech support he could. Answered some of my questions about the ignition system in general. I think I found those Permatune units for as low as $299, so you might want to check around if it turns out to be bad. Good luck.

RoninLB

77 911 with orig. Permatune till 2 yrs ago. It didn't fail, it's become back-up stored in lug. comp...I found their tech. reps. clear and helpful...Ron

aquabat911

I am running a coilless permatune on my 81SC and have not had asingle problem with it(furiously knocking on wood). when i was shopping for a new ignition the guys at permatune were very helpful and can't see them not wanting to help you. I have heard horror stories about the MSD, even more than I heard about the permtune. I think I would lean the same way as you and just get another permatune and save yourself a whole bunch of money, oh I think the tach adapter for the MSD is currently available.

TSN

From most of the posts that I have seen, the professionals who are on this board prefer the original bosch unit. I believe that you can have the original cdi rebuilt by Zims (?) and others for something less than $200, but that might be on an exchange basis. The po installed a permatune in my car as well that I replaced with the cdi which at the time -- maybe 7 years ago or so was some $400 new. Good luck. Tom