Thanks guys, yes it has been a bit of a shitty time of late. I did get on with the car yesterday and today though, which of course, didn't go as expected.
Long story short, I got the old manifold studs out, gave everything a scrape & clean up, installed the new studs and set to work getting the gasket and front manifold on. Torqued everything up, realised I'd forgotten the "yokes" (fat spacers) I'd bought from Nissan to replace the old ones, seeing as everything else was new.
Turns out I didn't need them and I didn't need to panic and remove everything again!!
Tomei instructions tell you to reuse the old studs and nuts, which I wasn't going to do. I should have just left the car as it was, rather than take it all apart to fit the yokes, which then meant the nut was half way off. I thought that the studs Conceptua sent me were wrong as they were shorter. Yep, they are shorter, because they are a newer design that use metal lock nuts (kenlock?) and don't require the yokes as they've got flanged bottoms. This means they don't foul on aftermarket manifolds and is why the Tomei were so easy to install compared to removing the old Nissan manifolds!
I wish I knew that before I took everything apart again!!
Few pics, firstly the cause of my leak! Turns out it wasn't a manifold leak at all!
As you can see, the heatshield is very tatty, so I gave it a quick wipe over with some degreaser and gave it a spray with some UHT paint on the outside. You're supposed to bake it in the oven or heat it to 160 degrees for an hour to fully cure it, but it gives off smoke and the wife is at home, so that'll be a resounding "NO!" then.
Actually, I could stick it in the gas BBQ and cure it that way!
It isn't brilliant, but still better than old metal and rusty grease colour! I've left the underside 'as is' so it shouldn't absorb any more heat than usual.
The Tomei manifolds are lovely, the build quality is awesome! It is a shame they will get covered up really, but hey, Nismo intake to go on, so who cares.
I'm a bit pissed off the Tomei gasket has been squashed when I torqued everything up, but I do have the Nismo exhaust gaskets still so I'll likely dig those out and fit them instead. I really don't want to risk a leak after putting all this back together, again!
I've got a few other bits too, Garage Yoshida A/C relocation gear surround (unfinished to I can spray it satin black, same as my interior parts), new cat temp sensor and a new water hose as the old one had split on removal. I then remembered I already have a blue silicone replacement with all the other heater hoses too. Oops! I'll get some pics up and hopefully get some time on the car tomorrow, we have friends coming over so possibly not!
Ah yes, and the reason I bought the Tomei manifolds in the first place! Broken bolts, broken drill bits in said broken bolts and broken bolt extractors too! It didn't help I'd just lost my aunt and my wife lost her nan two days later, so I wasn't in a great mental place anyway. Retail therapy helped for about 10 minutes though.