no idea on manual clutches-but I hear southbends are good
you will also need a turbo to hit 450..since it is a late model a gt38r
h2e/modded h2e is also a great choice but lot more money.
(not so much $ vs convertinga gt38r for an early 99 like mine)
fuel mods would help -itp or similar pickup-prepump filter ,larger lines,
reg return-possibly a walbro pump
will help a lil but not much
I also like powerslot brakes and hawk pads.
some other minor tweaks may be nice if you have the cash.
coolant filter, fluid damper, etc..
at 450 and a gt38r studs are not 100%...but nice to have
oh most important if it is a 99, and the cupholder has little lame rubber fingers....swap it for a newer style
the only thing that will do is sling flaming hot cups of coffee everywhere,and anywhere...cans are somewhat ok
but forget anything in a cup.