This is just based on information we know that is readily available.

Step 1, remove the output vat of the sale:

SRP / VAT = 89.29% of SRP

Step 2, remove the excise tax, assumed profit margin as supposedly declared by an executive of Honda which is 6%

After that, you need to know excise tax rate which is as per BIR

a. Excise Tax for MV (source : Excise Tax - Bureau of Internal Revenue )

0 to P 600,000 - 2%
P600,000 - P 1,100,000 - P 12,000 + 20% in excess of P 600,000
P1,100,000 - P2,100,000 - P112,000+ 40% in excess of P1,100,000
P2,100,000 - over - P512,000 + 60% in excess of P2,100,000

For this arguement, lets assume a sub 1mphp vehicle but more than 500k php so that we have a basis.

Excise Tax would be around 6.5%, Dealer profit claimed at 6%. That is 12.5% of the the 89.29%

As for the tariff, the Tariff Finder site states that based on ASEAN Agreements, tariff is 0 for CKD vehicles, Jpepa though unsure now as the site declares it as S (Special) for CKD and disallowed for non-CKD vehicles.

I would assume for discussion purposes that the Overhead costs to ship, store and sell/market the car here ranges between 15-20% (not too high, not too low)

So that would be 12.5% + 15-20% = 27.5% - 32.5% of the 89.29% SRP. results in 60.27% - 64.74%

So I would say the approximate value before shipping is around 60-65% of the SRP we are buying it at.

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EDIT: Luxury vehicles have a completely different tax rate especially if they don't originate from Japan, Korea and ASEAN region. One of the main reasons why a vehicle like BMW is selling for double the peso value than what you can buy it at in the States.