goto autobarn and buy a timing light
thats all you need
once engine is warm and running use the timing light (it will come with instructions) to read base timing
for rb25 it should be bang on 15deg. if you get any other number, your CAS is offset and must be adjusted
when i say offset, as in, it is dialed forward or backward. at idle, the timing is locked so for rb25 it is always 15deg
so if your timing light said say 12deg, then this means your entire tune is 3deg off, which means it will be sluggish
the ECU assumes your timing is bang on as per the CAS and won't know if its offset (ie backdialed/forward)
once you adjust, run a check with timing light and keep going until you get to 15deg at idle