i say 40psi. depends what you buy, a regular hx40 i believe has the 57mm wheel.
i have a super 40 that has a 60mm wheel.
it might be better to get a hybrid or convert yours.
depends what other mods you may want to do
sdx injectors come from sdx theyre a sponsor on here. i had an hx40 before my phatshaft. i would have to say spend the extra couple hundred and get a little bitter turbo so you dont have to upgrade twice. i hated my hx40 only had it for 3 or 4 months before finally gettin a 62/65/14 best investment i ever made
You get buy a new wheel and front cover for your HX35 to make it a 60mm. I would do that before buying an HX40. The shaft will be the weak link and like mentioned before it will break if you bark it too much.