There was a recent discussion here that lamented the absence of authentic South Indian in Manhattan. A big difference with the real stuff and what you find in NYC is the spiciness. Authentic South Indian takes the average American palate several months to get used to; if it was served here, places would quickly go out of business. (But when the taste is finally acquired, even through bouts of Delhi belly and other gastrointestinal ailments, it is well worth it!) Some places in Queens (and NJ?) come closer, but still not close to the real goods.
A quick perusal of posts on Thai and other SE Asian places on this board, if you haven't tried going to them already, reveals the same.
I've encountered one dish at one restaurant that lives up to what the eye watering mouth burning sinus opening spiciness of the original should be: Grand Sichuan branch at Lexington and 34th's sichuan huo guo (hot pot). This branch is under the supervision of the same chef as the Chelsea branch (despite what a muddled NY Times article last year indicated...)
This dish is not served to every customer. It is only written on the menu in Chinese and therefore only accessible to those who can read. This is prudent. Last time I was at this great restaurant, the people at the table next to me insisted on returning a dish because it was too salty.(!) People like this should not be eating at Da Sichuan; they are potentially ruining it for others and are better off patronizing their corner Guangdong take out or other less salty fare. If the hot pot part of the menu was in English (it's the only part that has not been translated) I imagine the place would find itself barraged with complaints of irate diners. Also, huo guo is relatively labor intensive, needs special equipment at the table, and time consuming (the reasons it is not served at the more crowded Chelsea branch), and to have shocked diners send it back would be a logistical and financial nightmare.
If anyone has found a dish spicier than the sichuan huo guo at Da Sichuan at Lexington and 34th, please tell!