I have over 300kw/4WD and still can't match your times. Practice and suspension set up plays a big part in that I think. I struggle big time with corner speed.
NT01's will be fine to drive to and from the track on but I'd probably run a wider front tyre if I were you. See if you can get the 255 to fit on the front, if not a 245.
(Shameless Plug)
If you're looking for breaky before race day, pop in to Bouwmeesters Bakery and grab a bacon & egg Roll
(The one with the glass fencing, tables & chairs outside).
Can I ask what happened to your pump? My car sits for maybe 3 weeks max at a time and there doesn't seem to be any issues but a couple of weeks ago I put the car on the dyno and the pump seemed to be struggling. (Walbro 400 making 300kw on -7s so should be plenty of head room).
The 86 boot must be a lot deeper than a 32 boot if you can stand the cans up as I haven't got a hope in hell of doing that in my car. I think I can fit 3 maybe 4 of the Supercheap cans in my boot.
10K for a basically standard spec build and I think it's another 3K or so for a stroker correct me if I'm wrong.
That includes a tune and other minor bits as far as I'm aware.
Fuel and boost also make a difference to the pipe diameter required.
At the moment I make close to 500HP at the engine on E85 through a 3" pipe but that doesn't mean I can't make more by going bigger.
For 250-300rwkw on an LS1, a single 3" pipe would be fine.
Yeah I wouldn't risk it. You'd need 5+ Jerry's just to make sure you'd be able to race all day and get home. I don't know how'd you'd fit them in a car with whatever else you need to bring.
Safer just to trailer it.