Good to hear!
I've had my TFS TW heads now for about 3 years (I think after the valve guide fix) with no problems whatsoever. Anyways, I had to call them up about a couple questions and to get the screws for the EGR stuff in the back of the heads and they were very helpful and knew their product very well - which is sometimes hard to come by these days.
Take care, E
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1991 5.0 LX Coupe - 38,000 miles
13.17 @ 106.14 mph w/ 2.138 60'