I have used Guhl on my two previous ZX-14's and he is very good. On my new to me 2012 ZX-14r I bought in Georgia I took it directly to Ivan who was near where I picked the bike up. If you are not racing the bike just get it flashed. If I was really picky I would also install a PC5 and autotune and usr Rooks tuning procedure. I picked Ivan because I had used his jet kits and found them spot on. For street flashes I would pick Ivan since when developing a flash he buys a bike and puts a lot of time into getting it perfect both on the dyn o and street riding it.