My father recently bought a automatic 2001 90 series prado with 230k on the clock and completely stock. Since purchase he has put in 2 inch suspension lift a 3 inch exhaust, 3 inch stainless snorkel and a bullbar. The engine is completely stock nothing has been added there and he wants to get it dyno tuned. I'm wondering since there's been nothing done under the hood how much more power he will actually recieve. He plans on towing a 3 ton caravan with it and possibly putting 31 inch tyres on it, what are your thoughts and advice on this as I don't want him to waste a bunch of money.