ok, not being racist, but why do u think 'chinks' are easier to blend in?? u mean, thailand is a part of china??
secondly, ur question is very open ended. u want to buy over restaur/hotel. budget? u know how much it cost or not? although thailand is cheap, it is not that cheap....
i mean, u can open a bar joint with 100k+ bahts ( 4-8k sgd), but u can also open a bar joint costing 10 million bahts. it depends on what u want. recently, i surf the net and found a hotel villa for sale in the suburb of BKK. u know how much it cost? 20 million baht.
but i suggest that if u are looking to open a restaurant, better save ur money, as the turnover rate is high. unless u are those famous restaurants like tawandang, or the smoke house in khao yai, which they can be considered as hi-so or even tourist attraction. but again, these types of restaurants can and will cost more than millions of baht. and yes, seriously, if u are interested to do business there, u need to know a few thai people there. for convenience sake. but of cos, if u have money to burn, many property lawyers are able to service u.
finally,why do u say cab drivers always ketuk ur money? those cabs should and must have meters. even if they ketuk ur money, its only 100 plus bahts. unless u are saying u took a 100 baht worth of ride, but they charge u 500. u must remember 1 thing, cab drivers hates jam ( although this prolong the trip, thus earn more), so sometimes, they might go a longer, but smoother way to ur destination. i take cabs in BKK, and i don't speak thai to them. but they never try to ketuk me. and i considered thai taxi charges to be very cheap already...
hope it provides u some clue..