just remember swapping in a beta adds a good 300lbs to the front right off the bat. and remember; all the 1.5 alpha (no matter if its a base SOHC or the GT DOHC or even the new 1.6 DOHC) AND the 2.0 beta were originally designed to be run with forced inducton. and if you put teh larger beta in there will be absolutely no more room for a turbo compressor and piping; or at best it will fit VERY tight and youd probably have to look into other radiator options as you will be very close there.
and its fairly expensive to make even the 2.0 push out 180whp.
$1000 for beta motor and tranny
$2000 easily for cams; balancing crank; pistons; overbored block; rods; exhaust; ecu; headwork; intake manifold work; BBTB.
whereas you can get rods and turbo pistons from a turbo s-coupe that drop right in cheaper than any aftermarket pistons. and the money you spend on cams alone will buy you a nice garret t3 turbo or similar and with an intercooler and good tuning youll be at 180whp right from the get go if you set it up right. and youll be lighter.
but remember i am very biased toward FI over N/A but however you want to build your car is quite fine i was just throwing out options.
