Do an engine diagnostic search, clean your throttle body. I think there are 2 idle motors, clean the one that wasn't replaced. Check and reset TPS. Most likely one of those.
I would do that with maybe a 1.2mm H/G, dont drop the comp much as youll mess with the piston/head clearnace. BUT you need to cc everything, dont go on what ive said, as rb30et pistons vary, and the head may have been decked(mine or yours) at some time which will effect the result.
Pretty sure it will be optical pickup. Check dwell as Zoltarc said, and should be -ve edge ignition output, although as a plug in, all this should be setup already
Building one at the moment, ACL race series RB30ET pistons, ends up between 8.5 and 9:1 depending on headgasket thickness, im going for 9:1(1mm headgasket)
You cant, just use all the rb30 bottom end biits with the rb26 head and accessories. Before you start read the whole thread, and cubes pdf. link, just read 15 pages a night, everything you need to know is in the thread.
Those turbos are rated at flywheel horsepower, therfore the one you picked is smaller than a gt35r. Plus they are gerret turbos with a different code, so it is probably a gt30r looking at the trims available. 44mm should be about right, but there is a thread in here on how to calculate the size
Still doesnt solve the compression problem. The VCT camgear may be stuffed inside allowing the timing to flop around, maybe a busted spring inside it, never heard of it but....
Sorry mate got me stumped, looks like i neat setup, just ope you have some spacers/washers behind the cas, or it will break the cas when bolted down, common problem when not running a cover.