Exactly
Pre purchase might tell you something you've missed, it also might miss something vital and leave you with a false sense of security
If you're planning to do it up, buy one already done up and save yourself some coin, or buy a dirt cheap neglected project to refurbish - no point buying a mint stocker to then spend several grand more on doing the basic modifications everyone else does anyway
If you're planning to leave it unmolested, buy from a dealer with a comprehensive warranty (double points if you get it pre modified with that same warranty, then you have some wiggle room for fiddling)
And ignore the "reason for sale" - people sell cars because a) they need the money (house, travel etc) b) they want to buy something better/different, or c) there's an issue and they want to flick it. Private sale is always buyer beware no matter how trustworthy they may seem. Except me I'm like totes legit babes
Oh my strongest bit of advice is try driving a few other options - don't just get your heart set on this one model and look for the best example you can - you might drive something different and go oh hory sheeit this is way more "me". Please see: a million examples of import owners turning V8 or what have you. My workmate had his heart set on his dream car - he got it (R32 with 25DET) - 3 weeks later he's swapped for a 180sx