To give you a feeler for what building a 7m costs...
I've spent about 14k on a motor/head/new parts/ and supporting mods and am probably sitting on about 340whp w/o tuning. Another 1k in parts I should have 400+ w/ tuning.
To get the 7m to a point where it was ready for more power...cost about 2k for a fresh motor, 2k in JDM/OEM parts to get the car as mechanically new as possible (you'll be surprised how fast hoses/gaskets/wiring adds up), 2k for headgasket+work+machine, and I guess I'll count 2k for tranny supports stuff (I have an auto)....then after that...probably 5-8k in supporting mods to turn boost up...and the rest was aesthetics and upgrade parts.
For 350whp, 7m might actually be cheaper to build for you, but for more than that...you might want consider other options. I stuck with the 7m cause I wanted the challenge.
I don't know what it costs for a 1jz swap, but I would imagine a 1jz...if you do the work yourself...will be slightly cheaper if you plan on more than 350whp...but the jz series costs are somewhat foreign to me.
Will you have to buy as many oem/jdm parts as I did to make your motor capable of supporting 350? I don't know. I just like the feeling that my car is 99% mechanically new whenever I go under WOT...what it comes down it is...what's your power goal and budget? And are you married to the 7m or JZ series? THe one thing to keep in mind is...once you start feeling 290whp...then 340whp....YOU ARE GOING TO WANT MORE! I first started out wanting only 300whp...then it was 340.....now it's 400....supraddiction is a disease...so keep that in mind!
