I'd go for a NOVAROSSI or a Sirio EVO3. I went from O.S to novarossi and i ain't going back. Everyone at the club that I race at that uses o.s engine have problems with glow plugs poping like mad. I had that problem as well and started to get sick of it. The "engine guy" at our club has managed to make a Nova last 2 years and is still winning races if you do get a Novarossi get a LL3 or a LS3 or if you run outlaw get a 5 port version (LL5).