2003 3.4 v6 hilux.

Spaanderman65
My comments relate to my experience with a landcruiser v8 diesel, so a different animal I know
In all I fitted 3 inch exhaust,(taipan from memory) K&N airfilter, Safari snorkel, and a DP chip
Landcruisers suffer from a lack of air, the factory snorkel is too restrictive, it could only rev to 3500 rpm, and you could hear the loud sucking from the intake.
For my 2 bobs worth, don't do the exhaust without considering snorkel and K&N, no good freeing up one part of a restricted path, do the lot. As soon as I freed up the airways, it reved fully, less intake noise, nice note, a lot more power, torque - lots of benefits
The chip? I fitted a DP chip, and yes, it went hard. Faster to rev no doubt. Around town, slow work, awesome. But when I drove it over from Karratha to Cairns, the fuel consumption was appalling, I disconnected it. (permanently) - Now to be fair, it was adjusted high and I could have adjusted it back. But my eyes are a bit poor, and the adjustment pot is tiny, I couldn't see if I was increasing or decreasing - so out it came. And I never put it back in circuit to this date. Its still mounted in place, but I leave it unplugged. The airway mods are enough.
Note this ramble relates to a different car and may not be totally relevant to yours. But remember, airways start at the snorkel and end at the tailpipe. Any restriction anywhere will negate other improvements
Costs? I truly cant remember, but as a guess, exhaust $1500, K&N airfilter $300, Snorkle, $300 and chip $1100
I still have the cruiser (sits in my shed since I bought the Iveco) and still love it, going great. I take it for a blat when I need a v8 fix. Good luck with your project

regards
Jim

I had one of those beasties. As I recall they took the prado intake plenum off and invented a much shorter squatter one to make the engine fit under the hilux bonnet. A body lift of the car and a prado plenum from the wreckers gives them back the prado ponies and better fuel economy as I recall. Not quite the easy answer you wanted, but chipping a short torquey plenum isn't going to yield too much. Trd also do a bolt on supercharger and 7th injector kit for the 3.4. A great hp boost and good on fuel unless you go racing with it.