[2_Liter_Turbo]

Adding a bit of input since I've done a very similar things.

First off, you don't need to re-machine guides each time you adjust lash, where the heck did you hear that Andy? LOL. You can order a range of guide sizes from Tomei or Nissan. You DO have to machine the rocker arms once for clearance. You also have to modify the tips (per Tomei's instructions) on both sides no matter if you run shims/guides or dual guides.

BC products are generally junk. Now, I haven't had experience with their valve guides, but their cams are trash (inconsistent love separation and profiles for example) and most of their stuff is sourced out of China. If you want to be cheap, run supertech valve retainers. If you run supertech springs, get the softest rate they have (can't remember the rate off hand).

There's some debate from a few experienced SR engine builders on validity of oversized valves on an SR. Dale Malone out of Australia swears that stock size (or even smaller like the GT300 SRs) is king. I personally ran +1 on both intake and exhaust, and the head flowed well, but not as well as heads from Dale Malone... LOL. I'm doing my own research into this, but I am a long way off from coming to my own conclusion (I have about 6 heads I'm scanning, flow benching, and sectioning for research...).

Intake manifold is a huge player in your powerband. Stock intake manifolds are awesome for street driving or Auto-X where on/off throttle is constant, and you need your torque curve lower. Intake manifolds like the Greddy will be much better if you are planning on spinning RPM. BTW, DET heads run out of air around 8,500, so there's no point in running them past that in terms of power, I only went to 9k on occasion when I needed the gearing on the race track.

For reference, my old setup was an S13 DET with headwork, Tomei 260s, solid lifters, supertech springs/retainers, +1 Ferrea valves on both sides, and WPC treated cams/rockers/valves. Machine work on the head was about $1,500 at Portflow in SoCal (this was in 2010-ish). Block had 9:1 CP pistons (Good rods, bearings, and all that jazz) and I ran 740CC injectors on a Greddy manifold. Full-race twin scroll GT3071R (again, this was 2010, so older tech here) kit. Car made up to 465 on a pump/C16 mix, 425 on 92 Oregon gas, and 400 even down here in AZ on 91ACN gas. I had good TQ from 4k to 8.5k and the car felt awesome. I also had the same turbo/injector setup on a completely stock (From valve cover to oil pan un-opened with a stock intake manifold) and it made 342whp/336TQ from 2008 to 2010 reliably. Only tore it apart for the engine build. Engine had about 200k miles on it. Made gobs of low end TQ, but fell on it's face at 6,500 RPM. So that'll give you an idea on intake manifold/cam difference.

I'm rambling on and I need to get ready for work, so if you have any questions, just ask.