can someone suggest me a MT PTP link with MIMO for 20 Kms in under or around US$200????

working on a very tight shoestring budget....

for your budget LHG is your only option. It should provide a usable link. What kind of bandwidth do you need this ptp link to carry?

bandwidth around 18 - 20 MBPS  ( 150Mbps )

i also found that LHG does not have " N " which is shocking in today's date and age...

What "N" are you missing?
It has fast ethernet port only so forget about higher speeds than the port manages even the wifi could be much faster...

Sad!!! device looks good but might perform bad

Buy and try it, I buy for test my impression is compare performance and price is nice, not nice but very very nice. It is not best, but price killing, dual chain 802.11n 5GHz, nice antenna gain, 100Mbit Ethernet, again dual chain give you possibility with lower signal to have 100mbit transfer what is limit on Ethernet.
I would like to see some device with gigabit port, higher power, 802.11ac, but existing model because of price (on some dealers it is cheaper that SXT5Lite) it is very cost effective solution for client and ptp links.
I try on 10km link where need 15 Mbps and for that price I am very satisfied.

so do you think i can get speeds comparable to the Mikrotik Sextant ??

i plan to use it for 18 kms.....

Yes I thing, why because SEXTANT have gigabit ports but 18km is to much it will have low signal and in that case gigabit port have no effect. With LHG you will have almost some signal because they have higher gain antenna and lower output power at the and they only one thing left price. 
My opinion is for that link you have some performance with SEXTANT and LHG but look price.