Hi Phil, I've had experience with upgraded clutches so can hopefully give you some of my experiences.
I had an ACT Street clutch and it only lasted 12k before starting to slip. Others have had more out of them but I can't recommend it given my what happened to me.
I chose between the Spec stg 3+ and HPF Stg 2 and really regret not going for the Spec clutch. It seems they are holding up much better than all the other brands out at the moment. The HPF clutches are starting to weld together after hard Drag strip use.
As far as the DMF is concerned, I bought one for just over £400 from Buypartsby as they were cheaper than ECP or GSF. The original one is LUK branded which is the same as what those companies supply. I wouldn't be keen on reusing a 97k DMF considering their design and the potential for failure.
I DIY'd my clutch the second time around so give me a shout if you need any advice.
BTW one thing I hated about the ACT was that the biting point was much closer to the floor and since it is heavier than the original clutch, it was a pain in the ass. From what I've heard, the Spec has a slightly higher biting point.