yep, and hes right, there is really no reason to replace the intake manifold unless your going to be pushing insane amounts of boost! that manifold will hold just fine. whats your HP goal? if its a low goal you really dont need to do anything to your engine to get it ready, just need to start buying a kit and some nice gauges and slap it on! then before you crank the boost up to high, Get a tune! if you want a affordable reliable kit just stay in the low boost range.
heres what i did with my scion, the scion came out in 2008, and i turbo'd it in 2008. all custom. no one made anything for it. first i got all my parts and put the turbo on with a A/F gauge and a boost gauge. and i was running 5lbs of boost with stock everything. finally got some better injectors made for the scion tc (perfect fit) then when i had the money i got a AEM FIC piggy back system and a tune and finally turned it up to 11PSI for safe daily drive ability. (but i kissed my warranty goodbye
but you dont need a piggy back system, and you have no warranty to worry about.
so it really depends on one thing. How much horse power do you want? if you want to really raise your numbers. you have a lot of money and engine work to do. but even 8PSI with a tune, would be a big deference from what you have now.
id start with a low boost turbo setup and go from there. if you want more boost, change out the appropriate parts later and retune it with the new parts etc