Yes, but in later years, and I believe RPW used to make a kit. RPW is really expensive for the minimal amount of possible HP gain, and the later 4g15 engines wont fit(wrong side). 4g15 in our cars came in 8 and 12 valve versions. The difference between 8v and 12v' are vast, its kinda like mitsu's overhaul instead of a simple upgrade. The 1.6 4g61 came with 16v though.
These values are for US spec cars:
4g15 8v(1.5L):81 HP
4g15 12v(1.5L):92 HP
4g61 16v(1.6L):123 HP(super rare, unless you pull it from a Hyundai)
4g61 16v turbo(1.6L):135 HP(rare)
BTW the conversion to DOHC for the 4g15 nets you 103HP.
meh
http://www.team-bhp.com/forum/modificat ... bishi.html