We have campaigned Nissan Sentra's at Racetracks stateside since the 1990's and they are cheapest to maintain and modify as far as the B13 and B14 SE-R's that are sold in the U.S.
Cheapest bang for the buck cars
Aftermarket is plenty for the SR series engines if you decide to swap in an SR motor.
i'm now currently using a JDM B13 Sentra SuperSaloon in the Philippines running an all stock GA16DE engine with non lsd tranny with just suspension, brakes, chassis Upgrades with sticky Federal Tires and it is pretty competitive at the Circuit track RWYB Series at Subic Raceway in Bracket B, C, D and E classes.
Internal Engine mods for the GA and SR series motors can be found at
JIM WOLF TECHNOLOGY, INC. / NISSAN PERFORMANCE / NISSAN RACING /INFINITI PERFORMANCE or
www.Gspec.om
Tevs