I had a feeling it would of been your spark plugs. I just bought a set of plugs already gapped to 0.70 I think its the ford LPG plugs.
Wow you got a bargain mate I paid 8k just for my ba xr6 turbo all stock with leathers, sunroof and tow bar and in phantom purple I was searching everywhere for one with all the specs above and in that color.. So I drove 16h there and back to go get it, This is a build for my kids they both have autism and have sensory issue's they love the feeling of a turbo kicking in so it's more of a project/any excuse to work on it in the garage and take the kids on a track or power cruise and weekend cruise and my goal is 10s because my vw gti does high 12s low 13s but it's my daily work car and I wanted a 4 door sedan rwd so I bought the xr6 turbo for a project and won't be selling it so I'll be going all out on it over time I've been hoarding heaps of parts for it over the past 5months and haven't even driven it in 5months since I got it.. I've just been flat out with work but I'm taking a break soon and getting stuff done to it hopefully.
I wish I could do my own valve springs but if anyones local and can do it for a cash job cheaper I'll be happy to pay less hahahah