I don't think your going to have enough clearance with header to mid pipe. I did the same and angled it a bit more, even then clearance is tight. You probably already know the 1zz intake is a restriction.

Strangely enough the primary intake pipe on the Sportivo necks down from 75mm to 70mm too, only over a shorter distance, so do you mean the airbox or cold air intake section, or ?
 
If I get an aftermarket intake I'm guessing that could put it out of tune with the Celica GTS ECU? Would I need a Power FC (?) or similar?
 
My thinking is to get it engineer approved first, before further mods..

The intake I believe is smaller on the spyder at 2.5" at the maf while the celica intake is 2.75" or close too at the maf. By using the spyder intake you will be over fueling slightly so going to a 2.75" intake will actually be correcting the tune. 
I made an intake using a 3-2.75" coupler and 2.75" maf + pod. Felt and sounded like a good improvement, I too had been using the spyder intake for a few weeks. 

Measuring my airboxes with verniers again tonight, both are 70mm OD and 66mm ID at the MAF . The place they differ is throttle OD, 70mm for the 1ZZ and 75 for the Sportivo 2ZZ. I don't have any Celica bits to measure and compare. Sportivo connector hose is 70mm ID one end and 75mm ID at the other. 1ZZ was 70mm ID both ends.
 
Any difference then might be down to internal hose taper, or the differences in the airboxes themselves?
 
Anyway, too short - not quite reaching. Rot my sox.
 
 
 

 
It lives! First start today at 3:30 pm. Ran for a minute, then shut down as rad not bled and lots of details not attended to yet, but the wiring harness prepared by EssDub worked perfectly.

Is that exhaust for real or just threw it on to start?

Just thrown on to start. Have to get a proper one fabricated.

Ah awesome! Mind you someone probably would use it lol not the stupidest thing I've seen on a spyder

Top rad tap finally bled when screwed out to the utmost.





Axle nuts on, but next time passenger side one off, new half shaft.. or proper die at least to clean threads... That "locking" by cold chisel idea was dumb Toyota.

 

 
https://youtu.be/UJDSUHrvEBk
 

 

 
Properly routed exhaust will be fitted this week, I hope.
In the muffler shop - should have her new system by Tuesday arvo.