The Fireblade is a fun little runabout. I like it for those "lightweight" races. It out corners just about everything, but in larger car races they kill you on the streights. You can put the mid or high rpm turbo on it or the supercharger. It has a high rpm limit, but seems to not sit at high rpm very often, at least for the races I use it it. It's always turning. So, I havn't put either of them in yet. Messing around with the gears and boosting the HP would help it out for the streights.
Yes, it's wasteful to spend so much money on it, but I waste lots of money on silly stuff for these cars. It's a game, after all. I like to be silly in them.