Maybe 181 can be extended to Jurong West N4/5 area?
The extention can be as follows:
After orginal route, Jurong West St 22 (Express), St 23, Ave 2
(Express), Corporation Rd, Ave 1, St 42, St 41, St 51, St 52 and
back to Ave 1.
This will provide a linkage for JW St 41, 42 & 52 to
Boon Lay Int and Gek Poh SC which are currently only served by 334
and 335 which goes to Jurong East.