Alright, all the following information that I provide as always has come from the Camry King SupaTouring Dave (aka The Viking). The testing + troubleshooting + speculation came from him, the irritation + annoyance to drive me to buy an ACV36R strut brace came from you guys and the brace came from me.
I've noticed alot of you Gen4 boys (especially the v6 owners) are having issues as to finding a suitable strut tower brace for your Gen4 and 4.5 Camrys. So far, I've seen 3 braces that have been linked but obviously have their downfalls:
1) Ebay strut brace - Pro: V6 and 4 cylinder compatible, provides some stiffness Con: unknown quality + longevity, most likely CCS (Cheap Chinese... Stuff)
2) TRD strut brace (PTR06-06991-01) - Pro: V6 and 4 cylinder compatible, clears TRD supercharger setup, very stiff, TRD quality Con: No longer in production, hard to find, cannot be found unused, expensive (initial 2nd hand cost + shipping)
3) Whiteline strut brace - Pro: very stiff, Whiteline quality Con: 4 cylinder only, doesn't seem to exist anymore
The Gen5 is essentially a rebodied Gen4 Camry and it is well known that the TRD strut tower brace will fit the Gen5 as easy as it will the Gen4 (with no clearance or bonnet issues). For reference, the standard Gen5 strut brace will fit on the Gen4 chassis but suffers from bonnet clearance issues as it sits too high.
Here is where UltraRacing comes into play. They make a great strut tower brace for the Gen5, which sits lower than the TRD + standard Gen5 strut braces. As seen below, the predictions that the UltraRacing ACV36R strut brace fitting the Gen4 V6 Camry were correct:
There is one issue however with the Clutch fluid reservoir as it needs to be unseated in order for the brace to fit. Using something like cable ties would probably keep it in place, you can see in the last photo where the black clip should fit in the reservoir. This problem only exists for MANUAL owners ONLY.
For those looking for a less ghetto way to permanently fix this issue would be to source a brake fluid reservoir from a Gen5 Camry (MANUAL ONLY) as the brake fluid and clutch fluid reservoirs are in the same unit. I believe the fittings are the same so it should be a simple, low-hassle switch.
So in summary:
The UltraRacing strut tower brace for the ACV36R will fit the Gen4 (and 4.5) V6 Camrys with little or no fuss (especially if you drive an auto).